There aren’t too many card that can recur multiple instants and sorceries, and being able to return one every upkeep of yours is pretty great. Charmbreaker Devils is expensive for a 4/4 creature, but even with the downside of getting something back at random, you’re almost sure to get another spell you’re more than happy to get back and use again. The bonus to power is a little rougher with no evasion, but if you’re able to clear the path, those spells you’re bringing back can help you get in for double digit damage. You have to find the right balance, so perhaps a lower count of spells will make sure you got a high chance of getting back what you want. Recursion is never a bad thing in EDH, so it’s easy to see why this card can potentially pack a punch.