I think it would be amusing if sometimes quoins got "confused" while your glitch is tripping on purple (or some new form of mind altering drug, perhaps a purple potion?), and energy, mood and iMG quoins were sometimes traded for another kind.
I wouldn't like the big value quoins being changed (although wouldn't mind terribly if they were) but I think having the normal ones being changed would be neat: super silly and very purple-esque.