Low cost, persistent, swift cards are something to be careful with.
Raising magic to anything near 14 is almost an instant victory, with unlimited attack at 14 magic and extreme attack power from about >10 magic.. not to mention you will also be cycling cards.
Yes, even 10 magic is a lot, but it's very much doable. Magic is the easiest facility to raise and there are also many other high G cost cards to make use of the high magic.