I wonder if it might be useful if you had a phone, a tablet and one or two other form factors - but when you rub your finger on the detector, it loads your environment.

but I can't imagine having to wait to use my phone or tablet. maybe the living room TV or the kitchen assistant.

I don't know if this is still the case but the last time I saw this discussion, someone with experience using the "shared iPad" education feature said it seemed like a massive hack, and switching users was seemingly implemented by "seamlessly" doing a full reset of the iPad to the new user, taking a bunch of time to backup the old user and restore the new one, nothing like a quick user switch on macOS, and nothing you'd want to use as a family handing an iPad back and forth.