They'll be full of cameras with fines and public shaming for anyone who leaves a mess.

It depends how it is presented. if you are a well-off customer, you virtual assistant will know all the things you like to do, what you might want to get, etc. and will suggest "convenient" stops on your way elsewhere. It'll remind you of all kinds of birthdays and suggest a stop at the jewelry store. It might always seem like it was saving you time, but in fact was nudging you towards more and more shopping etc.

I think, though, that fears of seat theft are exaggerated

statistics are a funny thing
I have had 2 seats stolen in the last 10 years

the bright side is that it is excellent exercise to ride a seatless bike