Japanese toilets have heated seats, warm bidets, disinfectant, maybe active suction, mood lighting, speakers, USB ports, Wi-Fi and whatnot.

What I’m talking about is being able to continuously control the water amount with the depth or duration of the “flush” button/lever press, which is a requirement to get an eco rating in my country, and such toilets have been common for decades. I think the similarly common 2-amount flush systems have a lesser eco rating and 1-amount flush systems are banned in most new installations.