Meanwhile in Japan (Tokyo at least) the red, blue, green, whatever lines aren’t even the same companies and good luck foreigner!
The issue’s it’s a bit too transparent: and after a while you realise that your suica is emptying unexpectedly fast, because you’re paying (and resetting your trip counter) every time you pass a gate, and that you probably shouldn’t blindly follow western trip system because you want to limit network switches, at which point you run into the issue that the resources for that are mostly in Japanese.
Then it depends how much the overhead is and how much you care.
It only works on JR lines, so in Tokyo you still need to buy tickets for all the private train lines and metro lines (city run and private run). Try getting around Tokyo on the daily using only JR lines; it won't be too much fun for you.
JR pass is only really useful for long-haul, intercity type journeys, primarily by shinkansen
Person above was talking about the JR Pass, which as you know is pretty useless for general "getting around Tokyo" purposes