I think custom classes would be an option If It was somehow possible to assign a class to a device from within verse. Because then I would just assign a class to each coin and increase the players class by one, if the player is collecting a coin. This way automatically all coins are unvisible except of the one that is matching the class of the player.
Do you know how to read/write to “Allowed Class” of VFX Powerup device or Collectible device from with verse code?
I have created this 
Feature request: Verse access to more device attributes