He means that a semi shot from inside a pocket will misfire. The pocket will prevent the slide from retracting fully and you'll get a jam. It might happen on the first shot, second shot, later, or not at all if you're really lucky but the point is you can't reliably fire a semi inside a pocket. Revolver is good to go.
Which is good news unless you were trying to shoot your dick off. In what situation would this sound like a good idea? ...
I think you guys are criss-crossed on PANTS pocket versus COAT pocket. Both have their place. I have some slash pockets on my Columbia jacket which would be good for this.
There's still a market for the 42, thats why. It's one of the softest shooting .380s you can buy, and with like 2 or 3 exceptions most of the other 380s in its class are garbage in comparison.
The Sig 232 is nice, but not really compact by most modern standards. It is basically a tuneup on the original Walther design.