I think that's the ultimate question, is Bitcoin's audit-ability/portability enough to head off fractional reserve banking on such a hard money standard. Will it repeat/rhyme this failures of gold...

I think the idea of proof-of-reserves/liabilities around with Bitcoin and "crypto" is one reasons it even gets there in the first place.

Even despite their lack of transparency, people can still watch known Coinbase address on chain like a hawk for macro moves. I think there'd be even more pressure for transparency at the state level.

Imagine rival countries accusing each other of not having sufficient reserves to back their currency and causing currency runs. There's only one way to innoculate for that, transparency. Bitcoin is for enemies in that way: the ledger weaponized transparency.