My IC (Mobile Suica on Apple Watch) backup is a Hello Kitty ICOCA which "brings me joy". The backup's backup is a PASMO with my name printed on it, kept because my name is never preprinted on souvenirs and I can loan a spare card to a friend/family so they don't need to stop at an airport ATM on arrival.

I noticed that longer haul local & rapid JR East trains with green cars allowed green seat reservation machine on the platform with a Suica card. There was a sign stating mobile Suica was not accepted. I don't know if it didn't integrate with mobile Suica's different form factor or was only compatible with a physical Suica card. I don't think most tourists are riding the Utsunomiya line very often, though. I should have made some time to stop at the Railway Museum in Omiya.

My mobile Suica was a little glitchy boarding Keikyu at HND upon arrival and the error condition was cleared/reset by the agent at the desk with the contact pad on the counter. So I carry a backup card and a bit of coinage just in case. Better to be a little over-prepared because I wander out to the inaka and occasionally come across unmanned and/or cash only stations.

ETA: Ah, glitch could have been the 6 month non-used Suica lock. https://atadistance.net/2018/04/26/u...he-suica-lock/ The "SF" menu icon in Mobile Suica does indicate I rode before adding more credit.

More easy, reliable, and fast transport payment options are a positive thing. Just because a tourist has a specific transportation system's pass or payments doesn't mean they'll exclusively use the pass, though it can be tempting until one realizes Tokyo's public transit works pretty well as an integrated system and staying off the Yamanote line is totally fine (or even desirable when staying near a major JR commuter station, trying to go counter-traffic in the morning). A local IC card is a nice complement. I'm not a local with a commuter pass or heading to Chiba/Saitama very often, though.