I think a lot of people who are anti-SS for some reason are trying to over-rationalise it. If you look at it sensibly and try and talk about working muscle groups, etc then it doesn't make any sense at all to take of your gears.
You can't explain the fun of a SS like that. Because it doesn't make sense, kind of like taking the long way home to ride over that big, rocky hill that's over -> there doesn't make sense either.
I can see why some people don't like it, it hurts, you can't have much of a rest without stopping and when you're running low on energy it's positively gruelling. But, if it works for you then it's bloody ace. It gives you a bloody great rush and you'll buzz like a kid at christmas.