Your bank wants faster AI. Your money deserves more than a promise.

If an AI tool helps explain a confusing financial document, I can see the appeal. If it starts moving money or changing an account, the standard should become much tougher. Convenience and authority are not the same purchase. McKinsey's new banking review surveys roughly 46,000 retail customers across 13 markets. Nearly a quarter report using generative AI for financial tasks. That is evidence of demand, not proof that banking agents are reliable or that their use has improved customers' finances. The consultancy's adoption case should be read alongside the controls it recommends, not as a reason to skip them. A separate DeepMind report offers a more technical reason for interest. Its human-guided proof work verifies selected properties of compiled libsignal code against stated specifications. A proof checker can examine the result. This is not verification of the whole Signal app, and it is not evidence that banks have deployed or validated the same approach. The connection is our analysis: as more work is delegated to software, assurances should become more precise about what that software may do. A narrow, independently checkable claim can be more valuable than a broad promise of trustworthiness. But the assumptions still matter, and someone must decide whether the specification describes the right behaviour. For a bank customer, that means keeping the everyday protections visible: clear permissions, sensible limits, ways to challenge a decision and a person responsible when things go wrong. Formal methods are a promising contribution to that work, not a replacement for the rest of it. We can appreciate progress without pretending it has already secured the entire financial workflow.