What "backs" the US dollar?
yes, the power of Fed.gov via the power of DOJ and the US Army, to force you, and the world, to accept them.
“what backs the US dollar”
USD can be stored in highly regulated and audited FDIC-insured banks such that a bank failure or theft won’t affect your ability to withdraw your funds ... that way, the back side of your mattress isn’t the only safe way to accumulate USD ...
right now, the so-called crypto exchanges operate 100% on how famous the guy who set them up is ... zero safeguards of any kind ... zero ... “exchanges” have only one principle: all your crypto are ours ...
tens of billions “deposited” by millions of crypto “customers” have permanently evaporated (stolen, actually) since June of 2022 ... and that’s not even counting the countless schemes that are out-and-out fraudulent on their face ...