A simpler idea would be to allow units to use row placement to target coins (ranged) or damage (melee). Doesn't have to be every card, but every faction has a way of dealing with each others "specials" (locks, purify, etc.), so why can't they have a number of dual purpose units and make more use of the placement?
Keyword like "tax", "bribe" or "steal" would work well. I'd also like to see the coin mechanic deployed elsewhere. Phillipa, for example, could be NR and SY - if you manage to steal (Kerrack Guard's order, maybe) then you can get value from her even in a NR mage deck. You get the gist - SK could "plunder" and turn coins into boosts, for example.
It's just plain wrong to have anything in the game that cannot be interacted with. Traps are bad enough, and there should be way more ways to deal with any kind of Artefacts, particularly as Locations continue to be on the rise yet you have no way of doing anything about it.