Been to Japan scores of times. Nobody but foreign barbarians walk around eating food. The concourses at the airports are spotless. A native will go to Starbucks and consume their entire purchase in the store.
You train out of Tokyo and pass a cement plant which is without cement dust. Workers are all about the facility sweeping and vacuuming up particles. The cleanest manufacturing places in the world.
When their beat cops enter an unsecured residence, do they take off their shoes too?
FWIW, in b-school, I took a course on design innovation, and Toto, iirc, was one of the cases. To inspire their toilet designers, they went ahead and imported toilets from around the world for them to study.
After the design and engineering departments got done, the marketing department set up a "International Toilet Exhibit" to generate publicity for the company.
I'd still be content with a plain old toilet system, white and 3.5 gallons...