The really nice advantage of Suica is its speed. Yeah credit card tap to pay is alright, but it's relatively slow, taking multiple seconds.
Now QR code payment seems to be taking off in Japan, but unfortunately you can't access it as a tourist.
Now QR code payment seems to be taking off in Japan, but unfortunately you can't access it as a tourist.
Similarly, it could also be implemented via a rolling payment hold loop. Unattended petrol stations do something similar: you first insert the card to authorize a hold (say $200), then fill up the car, then finalize the transaction - at which point your $50 bill is actually deducted and the hold on the remaining $150 is released. Transit could do the same, with only the very first transaction being slow, and each terminal containing a list of pre-authorized cards.