If everything else fails, I know I can still have two things to pay with: cash and crypto.
If "everything else fails" the internet has failed, and crypto will be worthless. Gold will probably still have some value, unless shit really hits the fan.
Then nothing short of planning a serious terrorist act can get you kicked out of all accounts.
Bitcoin doesn't store any energy.
Bitcoin is like a F1 car going around a track forever, with your name scribbled on it.
I think of them as representations of the idea that energy is (currently) so abundant and cheap that we can waste it on mining things like gold and crypto, a fundamentally ridiculous concept in terms of real actual human needs.
Once that stops being the case (when fossil fuel starts running out globally), the whole thing - cash, gold, crypto, stocks, bonds, property - everything falls apart.
Good luck buying groceries or paying the mortgage with Crypto.
(You conveniently left out “cash” from your reply. Cash. I’ll buy groceries with cash, if I can’t use my card.)