I'm completely guessing here (never been to Japan), but my guess is that these are ubiquitous in Japan.
In the US the trays are common in restaurants, because the transaction is asynchronous. Anywhere else (gas station, grocery store, banks, shops) cash is handed directly.
I'm guessing someone can confirm on how widespread these things are in Japan.
Yes - every shop/restaurant/store/etc I went into used them -from low end to high end. They are ubiquitous in Japan.
It took a minute to get used to it as I'm used to handing money to people in the USA. I found some of the people I exchanged with would hand me the money back, hand-to-hand even though I used a tray.
It doesn't end there - business cards, receipts and numerous other things have a very specific way of being exchanged that were different to me. But all very cool and novel for me. Definitely worth reading up on some of the basic customs if you travel there. There was a high tolerance for foreigners not knowing how to do things the "proper way" but it's always good to at least learn a bit and try.
In the US the trays are common in restaurants, because the transaction is asynchronous. Anywhere else (gas station, grocery store, banks, shops) cash is handed directly.
I'm guessing someone can confirm on how widespread these things are in Japan.