I've always liked "force to attack" effects and this is pretty much the granddaddy of all those effects. Forcing an opponent's creature to attack can usually give you a tactical advantage and this card twists the knife, as it were, by destroying the creature if it is rendered unable to attack. My favourite part of this card is its errata. It doesn't specify that the creature can't have Defender, just that it can't be a Wall. So those Axebane Guardians, Gomazoas, and Plumeveils will be in a lot of trouble when targeted by this. I wish it was a bit beefier or had Flying (it has wings!), but it's not exactly a deal-breaker.
Pros: Forces non-Walls to attack or kills them
Cons: 1/1 for 3, no Flying