The only annoying thing is, well at least in 2023 or so, was that you had to actually load the card with funds even if you had a payment method attached on the iPhone wallet. That got me once as I was tapping like normal throughout my time in Japan and ran out of funds and held up a bunch of Japanese schoolgirls (judging by their attire) who definitely laughed at me and I of course laughed at myself too.
If you’re in Japan here is a tip though. If you’re not super close to the main cities and you’re in an area without as many tourists and you see a group of Japanese school children and they all are eating something - the same thing or stuff from the same place, copy them. You won’t be disappointed. Probably. Had the best curry pan or whatever it’s called in my life following that trick.