>>2819711
tl;dr they're the most convenient option by a mile despite slightly higher prices, they often do campaigns so keep an eye out on that before booking.

You also don't need to talk to or interact with anyone. Go to the pickup area then unlock the car with the app. Once you're done just leave the car at your drop off area and again lock using the app.
Pickup/dropoff points are just random parking lots, no need to go through a store.
Comparing their prices to another company, Orix, then it's really not that bad given that you don't have to read/write and communicate in Japanese plus you have more pickup/dropoff options.
Get used to translating shit on your phone.

Given that you'll be here for several months(?), I assume you'll be getting a resident card? This might be the only hiccup when renting.
Failing that, they have an English website made for tourists and the process is more or less the same as Hertz or any other car rental shops.