A lot depends on how you play your game. For me, if a given location has 3 10HD badguys in a cave, and the 2nd level party pokes thier nose in, action points give them the ability to break contact and get away.
Of course if they decide they can just power through it by burning mass APs, they will quickly find out that wont work.
Of course if they decide they can just power through it by burning mass APs, they will quickly find out that wont work.