But I can only conceal my Glock with an IWB holster and a baggy un-tucked shirt, ie polo, bowling shirt, etc. I don't know about yall, but due to hot weather, work, and social situations it is often not possible for me to dress this way, and as such I cannot always carry my Glock. Often I can't.
Seeing as how I'm not totally convinced about the reliability of my PM9, I don't feel comfortable pocket carrying it yet. So, the S&W 638 gets pocket carried when I need to carry in a pocket.
Exactly.
That was my point about "practical" shooting competition vs. pocket holsters, too. Sure, top competitors don't use pocket holsters. They also wear clothes optimized for drawing quickly from whatever setup they need to comply with "from concealment". There's no rule that says you have to wear clothes you could wear to a meeting with an important client, or while working out, or whatever.
With a pocket holster, I can have the gun in the same place, and deploy it in the same way, whether I'm wearing cargo shorts and going to Lowes, or a suit and going to a theater.
I can put on a rain jacket and still draw it in exactly the same way.
If I put on a long coat, I can stick the pocket holster in the coat pocket, and still draw it in the same way.
That means no fumbling under stress. It means I can keep the gun concealed until I'm ready to fire, without moving my shirt up out of the way or drawing any attention to myself. It means I can ALWAYS have the gun, no matter what I'm wearing. It means the gun will always be in the same place, and the same muscle memory will apply.
That IWB holster might be ideal if you're wearing the specific clothes that are optimized for it. But if it gets cold and starts raining, and you put on a layer and a shell, you've just restricted access to your gun. Put on a long coat, and you've downright buried it.
...which brings me to another "impractical" part of defensive shooting that can't ever be replicated in "practical" shooting competition.
You don't know when or if you might have to use the gun. You might be hot and tired from a day laying tarpaper on the roof, and going to the hardware store for some more nails. You might be dressed up for the theater. You might be on the way to the gym.
If you draw attention to yourself in a group of people during an armed robbery or other attack, you may get a couple bullets in you. If you lift your shirt and expose a gun, you're likely to get a whole magazine. The armed assailant will ALREADY HAVE his gun out, finger on the trigger.
Those are some reasons I figure that real-world routine carry by civilians has a list of criteria and concerns that are different from carry by cops, and from any competition I know of.