This is an enabling concept and should be a key component of effective military (or business) doctrine. If every commander in the military had to ask the boss what they where supposed to do when they encountered an unspecified problem, how effective would they be?
Imagine the Tank Commander on halting his tank and radioing to the platoon leader "hey LT, there's a building in my way, what should I do?" and then the platoon leader radioing to the company commander... all the way up to the president. Wouldn't be a very effective fighting force would it?
The idea of "Commander's intent" is that it relies on subordinates having an understanding of what the overall mission is and how they fit into it. It specifically frees subordinates to act in accordance with their understanding of what they are being asked to accomplish. In essence, the commander formally recognizes that specific details are the responsibility of the lower echelon and it the the lower echelon's responsibility to make decisions about them. In our previous example, the company commander should have said "we need to get our tanks to the river. Responsibility for the specific maneuvers that are required to get there is in the hands of the individual tank commanders".
This is an effective tool, when used properly, that allows organizations to free themselves from the logjam of "lookup up" the hierarchy to discover what should be done. In essence, leaders at all levels have the responsibility for making their vision understood to those below them. They should resist the urge to constantly adjust the exact implementation details. In many ways, this is also way to reduce the amount of (micro)management that is necessary to get a job done and frees leaders to accomplish more strategic or visionary tasks.
I apologize to any tankers who might be offended by this silly example and I realize the terminology might be off, but hopefully the metaphor made sense.