The power condition in the U.S. is unstable. The AC power that runs your home theater is constantly in a state of flux. Sometimes there's too much voltage, sometimes not enough. Power can become so unstable that you can actually see it happening, like when the lights in your house suddenly begin flickering. during the worst case scenario, when your equipment turns back on, a power spike can be 200-300 volts.

Your expensive electronic home theater components are extremely sensitive to ANY increase in voltage, and can be severely damaged or destroyed by these unseen fluctuations in power. And, when it comes to surge protection, remember, IT'S ALL OR NOTHING... every possible pathway for surges (including coax and phone lines) must be protected.