Replying to myself here since the edit time expired: this does of course depend on where you live; in the context of the thread and the while fintech popularity in various places around the world and the EU not really having much use for that, this is because you can safely transfer money around without the risk of someone abusing your 'secret bank number'.
In the US and probably other places as well this is more like an SSN where just having the number allows you to do all sorts of (criminal) abusive things.
