Some American visitors were recently surprised when I said interbank transfers clear within the hour. The environment in the US is quite different to the rest of the world.
I find it really strange that it is not widely adopted in the US since it removes a lot of friction when it comes to paying for stuff ergo encourages more business. I.e. my usual coffee joint was always packed in the mornings and since they adopted NFC payments a few years back, I noticed the usual bottleneck queue of people paying at the cashier is significantly less unless someone starts jiggling for coins.
In Australia you're given a total, the cashier sees the card in your hand, asks "Paypass?", and bang, it's done. Entire transaction is over in <10 seconds, and the only customer interaction with the terminal is waving a card over the top of it.
Additionally, the lack of tipping means that people who pay with cash expect their exact change back and will wait for it, or will fish around for coins to find the exact amount, which slows down transaction processes.
Even worse, they're being signed up for an affinity card, which takes several minutes.
For the most part the holdouts have been restaurants, as many POS devices had the tip/authorize order backwards (if enabled, tap would bypass the tip step). That's changing now and I've been to a few restaurants with tap now.
A year or two ago I used to rarely see the contactless part taped over with a message saying "No paypass" or whatever, but I can't remember the last time I saw that anywhere. Even Costco now takes contactless up to $200 now.
[1] "[As of March 2016] only 3.5 percent of eligible transactions for those consumers are via Apple Pay, down from 5.9 percent in March of 2015 and 4.6 percent in October. Eligible transactions are those where the consumer has the right phone and merchants have the right enabling POS technology — that is the intersection of consumers with iPhone 6/6S’s and merchants with contactless terminals."
http://www.pymnts.com/apple-pay-tracker/2016/apple-pays-big-...
[2] http://www.pymnts.com/nfc/2016/uk-lessons-for-us-mobile-paym...