I can't say for Japan as I could not check but they can use them because support for them is present in their language...
This is the page that, amongst other things, mention how to use scenes for English (Canada):
see step 5...
I picked the English (Canada) one since English (US) always has the latest features which English (Canada) is always behind by a few months (but less than many other languages).
Now look at this page
see Passaggio 5...
See anything missing?
Yes... Support for scenes (and most of the other things in that section) is not yet present in Italian, looks like Google decided to release in Italy/Italian with what is most likely the most incomplete feature set.
I guess the only thing you can do for now if to either
Ok Google, Send feedback
and complain about this feature missing...
and possibly post on their forum...
Good luck and have a nice day!