Electronic – Would additional low voltage DC sockets be practical on mass scale?

In RL I noticed that power supply cables with possibility to charge one mobile through USB compatible socket actually exist:

I actually started to wonder, whether for purpose of world building such idea could be move much more further. I mean both electronics and LED light has to convert electricity to low voltage DC, so the voltage would be already converted earlier.

OK, so the question is following:
Would additional low voltage DC sockets be practical on mass scale for purpose of connecting small electronics and light?
(Safety gains? More efficient conversion at socket instead of dozens of tiny converters? Only less cable clutter? Extra: Roughly which voltage would be reasonable?)

Clarification: I'm trying to make a setting, which is technically modern-like, but quite a few technologies and standards evolved in different direction. Instead of too improbable ideas like steampunk, I mostly try to use ideas that are technically feasible and reasonable enough, just in RL turned out not to be specially popular. I really doubt, that's a good question for EE because, they can can reasonably answer, that right now in RL trying to implement such standard would be not worth the effort.

It's like question concerning airships, ammo, etc… just not so cool.