I can't think of anything in MoR that contradicts it, but in canon, when a wizard tries to pay a muggle, the muggle later comments about someone trying to pay with a bizarre kind of coin. IIRC, it's in Goblet of Fire, and it's the muggle who runs the campground where they're having the World Cup. He got memory-charmed afterward.

So he definitely saw some kind of wizard money.

Upvoted for an essentially accurate analysis. However a minor nitpick: The marginal fees and resources involved will likely make this not very profitable if one started out with a small amount of money. So it would make more sense to start out with say at least a hundred Galleons or so. (Incidentally, why are Galleons capitalized? Is that convention? Other currencies like pounds, dollars and euros aren't generally capitalized.)