Thanks so much for the feedback, Exylas!
So you are indeed correct, we added it in and had to drop the merchant dude in because we loved his aesthetic, but sadly other features got priority near the end of dev. However what he did was basically to allow the player to pay to remove current cards, ban cards from enemies, and add new cards to your deck as well.
Totally agree on the sound, it was the first thing on the list once I continued development pahaha!
With theme in mind I definitely get you there! The current state of the game was originally meant to be a basis for further dice rolls: Chance rooms where you roll a dice the size of your current deck to determine the outcome of a list where you can get lucky/unlucky and other effects; and some other card effects that use that same deck size dice in addition to some other mechanics… But you know how it goes with scope and time, gosh darn cost triangle pahaha.