If needing a safety why not buy a pistol which has one? I often ponder why some do not realize that a DAO semiauto is exactly the same as a DAO revolver? The revolver generally has no safety, but people do not seem so concerned about it.
Trying to rack a slide while under stress with wet britches and sweaty hands, one of which might be trying to fend off an attacker can easily result in a "short stroke" which will render your pistol useless at the one time ever when you will need it to save your life.
My LC9 actually has safeties galore, but I do not engage the safety when carrying.
Better to carry a big stick, it's ready to go at all times.