Kind of depends on the way you play the game I suppose.. S+S is only 10 points per second from what I remember.. If I have 4500 vitality, which I did at level 2 or 3.. that would take around 7 or so minutes to recharge fully from near zero vitality.. so, sure.. in some cases you're going to be riding back to town and doing some other stuff that takes 7 minutes and so get your vitality back up to 100% before your next combat.. but that's only with 4500 vitality and as far as I remember you can't further develop that skill can you?
I think S+S is good for when you have totally run out of all food, drink and other potions and you don't have the time or ability to go find/buy some food due to your current state in a quest or other. And as Chevy says.. it uses up a skill slot..
It's an "optional" enhancement.. nothing more. Choose it or don't. I don't agree that it's over powered though. I have not chosen to use it myself.