There's a reason this is uncommon. He totally changes the outcome of a combat step. Many times, your opponent will attack into your creatures, hoping to get some damage in, or content just to trade dudes. This not only blocks down an additional creature, but turns that trade into a loss for the attacker. On top of that, it leaves you one guy up to attack with next turn (assuming he didn't die in combat, which is totally reasonable too).

He WRECKED in ROE limited.