Okay, hear me out here. What's stopping us from just having payments be out of band, like with petrol? Is being able to ask your car to make a long drive acros

Okay, hear me out here. What's stopping us from just having payments be out of band, like with petrol? Is being able to ask your car to make a long drive across long distances on its own actually something people want to do? Or is it a solution in search of a problem? (Disclaimer, I live in the UK and not the US. It's possible there are cultural reasons I've missed.)