I can understand treating social network sites as less critical, of course.
The reason money-related systems often get singled out is the combination of irreversibility and auditability: a bad state transition can mean incorrect balances/settlement, messy reconciliation, regulatory reporting, and long-tail customer harm that persists after the outage is over.
That said, my point isn’t “finance is special therefore FP.” It’s “build resilience and correctness by design early”, explicit state machines/invariants, idempotency/reconciliation, and making invalid states hard to represent. Doing this from the beginning also improves the developer experience: safer refactors, clearer reviews, fewer ‘tribal knowledge’ bugs.
In other areas like lost sales or failures of the system there is lot more arguments. On other hand if you are rich enough and can prove the other side is off by sufficiently large amount of money you can bring the hammer down with facts.