If you put the Epic Chimeras Crown on and take it off again, it will substract dragonmark charges from your character. That would be understandable for a character who has rested and acquired "extra" charges (+1 greater, +3 lesser) and then takes off the helmet - the magically raised "maximum charge number" should go down again and any "above the (original) maximum" (= the "extra" charges) would be lost.
But the helmet will just remove charges (-1 greater, -3 lesser) from your current dragonmarks _every_ time you take it off - regardless if you have any "extra charges". Switching helmets 3-4 times will wipe out all your "normal dragonmark charges" - those you would have had anyway that have their source in your own characters inborn ability and should not be dependent on that helmet.
So you can't use any helmet clickie without depleting your own dragonmarks (which were one of the reasons to get the crown in the first place).
It's a nice piece of epic gear - but that annoying possibility of wiping out your marks right when you need them with an item that should give you more (not less) dragonmarks always left a bitter aftertaste for me...