Hi,
That's already down to what you mean by "consuming". Likely, you will need to destroy the coin itself, and also add 1 to the players coins counter. Because your coin has a network view, it must be destroy using photon, and will disappear from the game for all players.
If you need the coin amount per player to be accessible across the game, on all machines, then add a new custom property to the player, that's how you can synch all your players instances ( for example if all players shows their coins amount as a HUD or something for other players to know).
bye,
Jean