I asked myself the same thing for several years since I hate SVM.
The truth is this: most casual viewers use way too high contrast and saturation, especially since they keep the factory settings. Many people do not see a TV as a window; they see it as a fireplace, or an alien landing beacon, or a personal tanning screen. That is why they are perfectly happy with the fluorescent tomato people on screen.
That is what makes it so rewarding to make features that 'improve' picture quality, so casual viewers do not have to bother learning how to adjust contrast and saturation. SVM is one of those features. It is intended to compensate for the fuzziness that occurs when the picture tube is pushed way beyond acceptable contrast. That is, compensate in the eyes of the casual viewer.
So, most of us discerning viewers and HT buffs ask; "Why?! It doesn't make the image sharper, it just adds big fat bevels!". Of course it does. "My old TV had a razor-sharp image!" Of course it did. We know that well. But, the problem is, the casual viewers have never ever in their lives seen a properly adjusted image! They are totally unfamiliar with how good picture quality can get without all those 'features'.
So they love SVM, if only for the fact they can brag about it in front of their friends.