I was only disputing parent assertion that trust is a solved problem and that banks don't "need" a solution.

I haven't the foggiest if stablecoins solve these problems any better. In theory I think all participants having visibility into the ledger would at least answer the problem of "where actually is the money", but I'm not even sure of that though because of fiat on/off ramps, custodial arrangements, roll-ups that might happen off chain, etc.

I don't know if you could use smart contracts to encode a recall/dispute resolution process into transactions but that's very hand-wavey and possibly collapses under scrutiny!

All in I've no idea if crypto helps us here but I do think we have a long way to go either way.