You can do whatever you want with the card, but keep in mind that even the strongest 5 mana spell in Duelyst is something like BoA. Well, it’s really no contest that this card is stronger than BoA, because it’s an unconditional and instant 3 mana advantage.
A 3 mana advantage is something that you’re able to get with 3 Crystal Wisps or something, which is a play that requires 6 mana and 3 cards, and possibly multiple turn delays. This card does it in 5 mana, in one card, and in an instant. Also, It doesn’t even gain that advantage by increasing your own mana, but by destroying the opponent’s. That’s just downright unfair; nobody would want to play against something like that.
Imagine using the card on curve as P2; your opponent will only have one mana to use next turn while you’ll have 6 on your turn afterwards. That’s more or less forcing the opponent skip his/her next turn. No spell in Duelyst could generate as much value.