May I present a simple analogy.
When you drive by small cities and towns you usually see a water tower. The reason for these is to address peak water usage demands; usually in the morning before work and after work and evenings when the bulk of the population shower, bathe, do laundry and dishes etc. Without the huge tank of stored water under the pressure of gravity the population would experience a low flow, low pressure situation.
Now think of a power conditioner as a water tower and peak usage times as dynamic peaks in your music source. I think most people will 'get' this concept.
A good power conditioner enables an amplifier to perform better by allowing it to draw more current during dynamic peaks than it could ever draw directly from the wall outlet. A great power conditioner will scrub the A.C. clean and give an amplifier virtually unlimited headroom, thus increasing dynamics, lowering the noise floor, improving resolution which in turn expands the sound-stage and produces better imaging.
I get all this and more from my power conditioner from Silver Circle Audio. In fact, I liked it so much; I upgraded from a 3.0 to a 5.0. Every component I use just sounds better when powered by this conditioner and I can't imagine ever running my system without it.