I know you’re not being precise, but the term “backed” is not valid. For a currency to be “backed” or more accurately commodity backed currency, you must be able to exchange that currency for that other thing. I.e. money for gold. You can’t get the electricity back in exchange for your bitcoin. :)

Can you pay your electric bills in bitcoin? Even though dollars are not 'backed' by gold, you can still exchange dollars for gold. Just not from the government at a government-fixed price.

Well, that is a completely different thing. That’s just a market exchange of goods/services.

Sure, one way is government price control, the other isn’t.