a pcc is one of the most controllable weapons for self defense and the easiest (and cheapest) to train with.
the barrel length adds velocity thus enhancing the terminal effects of defensive ammunition designed for pistol length barrels.
just playing devil’s advocate vs your arguments, a ‘pistol’ ‘pcc’ (ex. a scorpion with a brace) requires no stamp, so you’d be covered there as well.
not to mention it can be the cheapest thing to shoot besides 22LR
I completely get it, and I tend to agree (and I appreciate the challenge to my viewpoint

). In a scenario where neither a handgun or a 5.56 braced pistol is an option, I could see spending the coin on a braced PCC in 9mm. But then, if it was going to be the "one gun," then why not go 10mm? (availability and cost of ammo could be argued, for sure). I feel confident enough with a handgun to see a 9mm PCC as more of a novelty, especially when a 10" or 11" AR pistol in 5.56 is a choice at a similar price point.
Here's a bit of data that I've looked at to come to my position:
(statement of intent)
www.ballisticsbytheinch.com
You can see that for the 147gr (my defensive load of choice) there is almost no value gained by adding barrel length. Even the 124 and 135 grains have what to me seems like a negligible gain in velocity.
I'm not saying PCCs don't get it done. My position is more like this: if I already have compact sedan and 3/4 ton pick up truck, why bother getting a 4- or 6-cylinder pick up truck that costs the same as getting another 3/4 ton pick up truck? I could just spend that money on gas (ammo).
Now, the person for whom I started the thread, he only has a compact sedan (handgun). So getting a 6-cyl pick up adds to his capability without being too redundant.
My mindset right now is that a PCC is on my list, but it's not useful enough to be high on the list. Depending on what happens with ATF/midterms and legislation (especially pro 2A legislation, if that's even a thing anymore... lol), I may move it higher or lower on the list in the coming months.