Wagtail
Horse servant
Dunno if I'd call it milder........less effective, less precise (not that a snaffle is precise) certainly. Many horses go better in a curb action than in a pinch action, perhaps because it suits their mouth/head conformation and understanding of the aid. Others respond to different areas of pressure; depends on the horse, the rider, the activity, the training, all sorts of things.
I agree you have to find a way that best suits each horse. I have known some horses that seem to prefer a curb bit. I never use a single jointed snaffle though due to the nutcracker action and the fact that the joint can dig into the roof of the mouth. The only single jointed snaffle I use is the demi anky which is shaped to eliminate these problems. IME one of the worst combinations of tack is a single jointed snaffle coupled with a flash or drop. Pull on the reins and the centre joint digs into the roof of the mouth which is strapped shut so no escaping. A torture device IMO.