Bits about money explains why: the (normal) financial system is slow for a reason: if a bank suddenly tries to transfer 5.6B all other banks will call their contact for confirmation and then take 2 business days to process the transaction, more or less.

Stealing anything is easy, escaping and converting to cash is the hard bit, and crypto makes it easy to vanish with your money in literal seconds.

You could treat them like bearer bonds. Split your holdings over multiple (like tens) of addresses. Sell individual addresses for cash. You'd need to do this via a trusted intermediary who could accept the cash and verify the address before making the exchange.

And yes, this is somewhat absurd. But so are online transactions that can be hacked with no backsies.

you'd typically sign on an offline, airgapped computer