Personally when I draw my snubby from my pocket, my thumb automatically goes on the hammer. Thus no snag. I like the option of having a hammer to cock if I have a need or desire to do so.
Thats my preference and may or may not work for someone else.
Also with my snubby if I get a fail to fire all I have to do is pull the trigger again, with a semi auto I would have to clear the round which takes more time than simply pulling the trigger again.