Title basically says it all. Is there any point in grinding and spending those 10k? Or is it just a money waster? Unless I missed something the only thing it does rn is that the person who shows you the third room is different.  So will there be any benefit at a later point or should I just keep the coin for something else?

SPOILER

The person showing you the room with the continuation of this event is a bit different + small dialogue a bit further into this event.

Also I plan to add event to recoup part of the money. Whether I add much more to it depends, but it is a possibility.