Some friends with camper vans were recently discussing whether to get 240v for their respective vans. The guy at the garage wasn't recommending it because of a

Some friends with camper vans were recently discussing whether to get 240v for their respective vans. The guy at the garage wasn't recommending it because of a lack of a 'use case'. I would like to see the UK ring main revisited to provide a useful USB power ring main where devices can negotiate current demands, e.g. to power a laptop without dropping the voltage for anything else plugged in to the 5v DC. How would a modern day government set a standard for that?