Huge shout out that if you are going to be in Japan, you need one of these cards. I had thought I could just buy a two day pass in Tokyo. Which, you can, but you are almost certainly going to be limited to what routes and lines you can use, then. Which is brutal when you can't tell google maps which card you have.
JR is better if you go to the countryside of Tokyo but for the city itself Metro is much more convenient, IMO. Perhaps it depends on the station you commute to, though.
When I travel to Tokyo, I usually do at the very least 4 Metro trips per day, and let's say the minimum fare is ¥178,it would come down to ¥712 daily.