Apple Pay Review: Easy to Use, but Still Hard to Find

You no longer have to be a geek to pay for something with your phone.

Last week, iPhone 6 owners got Apple Pay, a free service that lets you buy things at stores and inside apps using a digital version of your credit card and a thumbprint. Shortly after Apple switched it on, I walked to McDonald's without my wallet and bought McNuggets with a wave of my iPhone. It was so easy, the cashier didn't even notice.

PayPal, Google and others have been trying for years to get us to pay with phones. But their systems made shopping harder, not easier. Apple Pay doesn't require you to set up a special account or preload it with money. There's no app you must open to pay, no special password to remember. Even checkout is more secure than with plastic.

Apple Pay changes the way we look at our phones, not to mention wallets full of credit cards and bits of paper. It is the first such service I trust to be secure and consistently easy-fundamentals to taking a digital wallet mainstream.

But it is also just getting started. For the past week, I've been using Apple Pay everywhere I could find it-not nearly enough places for me to leave my wallet at home. A few shortsighted chains have even pulled support for it. To change our habits of paying with cash and plastic, Apple Pay needs more capabilities, like standing in for all of your buy-10-get-1-free punch cards that would give you more reasons to pay with a phone.

Still, Apple Pay is our best hope yet to put overstuffed wallets on a digital diet. Anyone with a new iPhone should give it a try.

To set up Apple Pay on an iPhone 6, tap the plus sign in the included Passbook app. You only have to do this once: The app will prompt you to add one of your existing credit cards by typing in its digits or snapping a photo. ( Find more setup details here.)

Apple Pay works with most existing major credit and debit cards, which you can add to your phone in a matter of minutes. The exceptions are cards from some smaller banks, store-branded cards and corporate cards. ( Apple is working to fill those holes.)

At the store, look for an Apple Pay logo, or more likely the universal contactless payment logo-a sideways Wi-Fi symbol with a hand approaching it. Once you're rung up, hold your iPhone near the credit-card terminal. You don't have to tap or swipe-the connection happens over a wireless system called near-field communication, or NFC.

When your iPhone gets close enough, an image of your credit cards appears on its screen, even if the phone is asleep or you're playing ' Candy Crush Saga . ' If you're ready to pay, lightly put your finger on the Touch ID sensor to approve it. If you want to pick a card other than your designated default card, just tap one, then do the finger scan. Nobody else's finger will work unless you've registered that person's print on your phone. (I tried.)

At most stores, that's it-you're done. A few might ask you to sign a receipt or punch in your debit card's PIN. In my tests, only one sales clerk got confused, and we figured it out together.

Contrast that with an experience I had earlier this year with the competing PayPal app while heading to lunch with colleagues. PayPal had hired people to stand in front of the restaurant, telling people they'd get $5 off if they paid with its app. But doing that required downloading the app, remembering your PayPal password, finding the restaurant in the app then tapping to pay there. Most of my friends decided they'd rather forego $5 than pay by phone.

Google Wallet and Softcard, a joint effort of AT&T , T-Mobile and Verizon that work on some NFC-equipped Android phones, aren't much better. Both require you to unlock your phone, launch an app and type a code. That's too many steps to be convenient.

Apple Pay may be simple, but is it safe? A number of security experts I've spoken with call it more secure than carrying a plastic credit card.

I know that's hard to believe considering that iPhones couldn't keep sensitive celebrity photos away from hackers. But with a regular credit card, your account details are relatively easy to steal. Apple Pay doesn't even store your credit-card number, just a unique code that's a stand-in for your card, hidden on a part of the phone that doesn't get backed up online.

If you lose your iPhone, you don't have to reissue all your credit cards. Instead, you can suspend payments via Apple's Find My Phone website. A thief shouldn't be able to make purchases with your phone unless they have your thumbprint or, egads, your thumb.

There was one serious hiccup in Apple Pay's first week: Some people with credit cards from Bank of America got repeat charges. But the bank recognized the problem and fixed it. Its response underscores one of the best safety features of Apple Pay: Because it is tied to a regular credit-card account, you're not liable for purchases you didn't make.

One of the biggest risks of Apple Pay comes from fraudsters who might enter stolen cards into an iPhone and link it to their own fingerprints. To ward that off, some banks ask you to confirm you're legit by calling a hotline when adding their card.

The worst part about using Apple Pay has been finding places that accept it. It works at over 220,000 U.S. locations, including national chains like Chevron , Macy's , Nike , Office Depot , Walgreens and Whole Foods . But even there, it may not be at every gas pump or checkout station. That's just a sliver of American retail, and a guy can only eat so much McDonald's and Subway. There isn't even an app-yet-that'll tell you which nearby stores take Apple Pay.

Job one for Apple now is signing up more merchants. Its system benefits banks and shoppers, but doesn't give stores much incentive to install the needed equipment. Apple Pay doesn't offer them cheaper transaction fees or additional information about customers.

Some stores with the right equipment, including CVS and Rite-Aid, have blocked Apple Pay. A competing service, CurrentC, will launch next year. Both of them are among its backers. Unfortunately, from early reports, it sounds like CurrentC will be a step backward in usability: You pay by scanning a code inside a smartphone app.

The hardest question for Apple Pay right now is: Why bother? Chances are you have your phone close at hand at checkout. It is a beat quicker to use Apple Pay than to retrieve and swipe a credit card. But just a beat.

I'd consider it more useful if Apple Pay could address my George Costanza-style exploding wallet, so overstuffed with junk it makes me sit at a tilt. To do that, my iPhone would need to store receipts, work on public transportation and unlock the office doors, too.

I'd be more inclined to pay with my phone if it also doubled as one of those loyalty cards I'm always misplacing. Even though it isn't as convenient as Apple Pay, I regularly use the Starbucks app to pay for coffee because I get a free cup every so often.

There's a ways to go before we're all paying for things with our phones. But Apple Pay has laid a blueprint for it that makes more sense than any option before.

Write to Geoffrey A. Fowler at Geoffrey.Fowler@wsj.com or on Twitter @geoffreyfowler.