For you to select the payment account, the terminal has to be able to show all linked accounts, then let you select one. Alternately, you'd need to use a mobile app that lets you do so during the transaction. Pulling the right piece of plastic from your wallet is much faster.
Wireless is not reliable enough
At one Disney World restaurant where I had breakfast, the waitress told me that if I paid via the Magic Band, she'd have to do the transaction away from my table -- and I'd need to go with her to enter my PIN. The reason: The Wi-Fi signal required by her portable payment terminal didn't work reliably in that area. I paid with plastic.
Surprisingly, Disney World has lots of available Wi-Fi in its parks and resorts. In the outside world, most hotels, shopping centers, and restaurants are much spottier in their Wi-Fi coverage. Of course, cellular coverage is also notoriously undependable and situational. For example, my Verizon Wireless signal in Orlando and Atlanta (my previous leg) was highly variable, ranging from 2G to LTE. Those areas are dominated by AT&T, so other cellular networks get the spectrum scraps. In my hometown of San Francisco, Verizon has better (not great) coverage than its competitors, yet the signal quality in a city can vary dramatically, even for the dominant carrier.
Any payment system that requires a live Internet connection is a risky one, because that connection isn't always available. Merchants need a store-for-later capability, which not all mobile payment services offer. Customers need plastic or cash as a backup, which means the merchant has to support them too.
Loss of battery life means you have no money. My iPhone 4's battery usually lasts at least 18 hours, unless I talk a lot on it. When I was in Orlando, a 45-minute conference call (which drained my battery faster than usual because of the poor Verizon signal) reduced my available battery life by a good 10 hours; I was out of juice by 3 p.m. That didn't affect the NFC-equipped Magic Band, but it would have meant I couldn't use a service like Square Wallet if I happened to have been at the convention center instead when that happened. Again, you need plastic or cash as a backup.
The services are too proprietary
When I was at Disney World, I could use the Magic Band anywhere. But it was just a bracelet when I was at the Orange County Convention Center. I have Square Wallet on my iPhone, but almost no one accepts it outside of Starbucks. Yes, in my home neighborhood in techie San Francisco, some small coffee shops do, as well as a few hair stylists and, oddly, lots of therapists -- but no vendors I do business with. I've found that to be almost always the case when I travel, too.
Many providers want to be the standard payment service everyone uses -- PayPal is the latest -- but none is anywhere close. So far, the credit card providers have stayed out of the fray, which opened the door for alternatives on the sales-terminal front end. (The credit card companies get the business on the back end, regardless, which PayPal would love to change. But don't hold your breath.)
Right now, the mobile payments opportunity is for providers, who all want a cut of the transaction fees. They try to appeal to merchants by offering lower processing fees than for credit card and debit card transactions. Their promise to users is allegedly convenience, but they don't deliver on that in any broad way. In many aspects, mobile payment is a technology looking for a market.
Sadly, even if there were a market, we need a monopoly for mobile payments to have a chance to work -- or an oligarchy as we have with Visa, MasterCard, and American Express for credit processing. We need to solve the other issues I've surveyed as well.
It may happen, but at this point, your best mobile payment method is the plastic card you carry in your wallet. At least it's mobile!
This article, "What Disney World teaches us about mobile payments," was originally published at InfoWorld.com. Read more of Galen Gruman's Smart User blog. For the latest business technology news, follow InfoWorld.com on Twitter.