This is one of those absolute statements that cause the kind of problem stated by grandparent. There are lots of those: "Use Postgres for everything", "No business data on the DB", "No methods bigger than 10 lines", "Abstractions only after 3 usages".

Back to the topic: Lots of potential bugs and data corruption issues are solved by moving part of the business logic to the database. Other people already covered two things: data validation and queue atomicity.

On the other hand, lots of potential issues can also arise by putting other parts of business logic to the database, for example, calling HTTPS endpoints from inside the DB itself is highly problematic.

The reality is that the world is not black and white, and being an engineer is about navigating this grey area.