It is the only way to approximate how many times the buttons have been pushed, how many files recorded (of course how many times the mirror, and shutter, have been activated), etc. In essence, it IS indicative of one thing: how much the camera has been used to take pictures. I would disagree with this conclusion, and, often, shutter count has a decided effect on resaleable value.

Do note that the total shutter count is indicative of exactly nothing.