[mrkeen]

* Most single-db deployments give up on ACID for performance reasons (see READ_COMMITTED)

* Even if you have ACID, it's not sufficient for distributed systems. Its guarantees will keep one node consistent with itself. No transactionality between the customers app and your db.

Maybe you're one bank with all the customers, but as soon as you want to talk to other banks, are you really going to share the one ACID instance? Who's the DBA?

Currently the state of fintech is 90% of devs being in denial that they're in a distributed system.

> proven double-entry ledger approach.

Yes. In that language, the ledger is the list of events. If today's devs were around 300 years ago they'd be calling for 'balances' instead of 'ledgers' because they're simpler.