While I'm ready to admit the S&W TDA auto's have had their day and time has passed them by, and I've owned an S%W 4506 since the late 1980's, I always consider the "backwards operating, slide mounted safety" argument a little of a head scratcher.
It's a safety/decocker. Unless required by your employer to use it as a safety, nearly everybody simply uses the device as a decocker. Round chambered, hammer decocked, safety off.
I'll use the safety if I throw the gun in a bag, or if it's placed in a nightstand drawer, but if I have the gun on me, the hammer is decocked and the safety is off. It's an added safety feature that can be used for some circumstances, but is not normally used for carry.