How would you say it is not big in the US? I use PayPass pretty much everywhere, from the gas station, to Home Depot, to Walgreens, to CVS, to Best Buy...I find it nice, as I don't wear out the stripe on my card, and I don't even have to pull the card out of my wallet, I just tap the entire wallet and go. The only place I have to actually physically pull the card out are sit-down restaurants, and places where I am required to hand my card over to the clerk. Most places here in Arizona have a PayPass reader if you're allowed to swipe the card yourself vs. handing it to the clerk.
The only notable big exceptions are: Walmart, and Apple Stores. Apple Stores I solved by using the EasyPay option in the Apple Store app. Walmart, I still have to do things the old fashioned way, but at least their readers contain Chip & PIN functionality, so they are future proofed when the US gets Chip & PIN cards.