True, although you have to periodically remember to top up you account (my last trip to Japan was short in duration so it wasn't worth it to get one; my memory is probably biased)

My experience, having traveled a lot, is that even those countries/municipalities with good public transit are still pretty confusing for visitors who aren't familiar with the system/haven't downloaded the right apps etc./are jet-lagged/don't speak the language. Some usability testing would really be welcome.