Japan is pretty efficient but paying at the table is still not really a thing. Most places have a button on the table to summon staff. Most conveyor sushi places let you order from a screen and I’m sure many restaurants in the city do this as well (I live in the country). However, I have yet to see a payment at the table system- most likely because Japan is still largely a cash nation. Overall the system is efficient, though there is some delay at register - probably depends on how crowded of a place. Still, I prefer this over the hover and try to get the waiters attention in US.