Idea of using electrum as a mechanic during duels=instant no in my book.
Again, this is more of a lulzy idea. It's not for a practical use because of it's cost. Unless you hoard up several thousand electrums, you will never be able to effectively use them.
Then why even introduce such a card idea? All this does is not inspire people to create more original or new decks, but just teach people that whoever has more 
wins a duel.
I find that it does. A deck possibly based on a nerfed version of the quanta cannon could be used as an effective nuker in terms of spell damage and creature killing. In terms of the Electrum weaponary idea, it's not very profitable to use it in the first place (Using it regularly will put you in the hole a couple thousand a math), but when you can, it is an efficient item to kill things with. Also, it's usually the person who has more electrums and rares that wins a duel. You don't see people with the starter exactly beat a fully upgraded rainbow do you?
Most duels sure, are based on money, but at least both players have roughly an even chance, and an unupgraded deck can do as well as an upped one. Your card just allows quantaless CC and high damage. Sure, it's not very profitable, but it'll be used to troll people in PvP a lot.
The person with a barely modified starter has a moderate chance against a well versed rainbow? Shenanigans.
Also, it would be a bit hard to troll people with, given the dedication to get it and use it. If someone does manage to obtain many copies, hats off to them.
