The gaze is one of those things that is not so hard to defeat if you know about it ahead of time...but most monsters won't. Compare it to an ubercharger, who kills without a save if he can get a charge off. A knowledgeable foe can easily deny him a charge vector, rendering his power worthless. But the tactic is still valid because most enemies will not know it's coming until they're smeared across the dungeon floor.