What does the coin pit in the crypt do?

[Sid Icarus]

I've put various amounts of money into it and it sounds like something is opening, but I don't see anything changing on the map. Any hints?

[PhamTrinli]

I think it opens a secret on the same level somewhere if you drop at least 100 coins. Not sure if dropping more affects anything.

[Sid Icarus]

Ended up figuring it out a bit later on

If you drop enough coin down the hole it piles up on a pressure plate in a room on a floor below and opens a gate