If implemented well, sure -- sometimes, maybe often, you can point a customer to a support document that directly answers their specific question and relieves some of the load on your staff. That's great.

But the execution matters a lot, and DO's is currently not great. IIRC, it takes clicking through a few screens of "are you sure your question isn't in our generic documentation? How about this page? No? This one then? Still no? You're really sure you need to talk to someone about this error? sigh Okay, fine then."

These systems should not be implemented as a barrier to reaching human support, but they often are.