At the Lucky Gunner shoot, Oleg showed up with an assortment of odd guns. Among them were the Kel-Tec PMR-30 and its carbine spinoff. I'd shot the PMR's predecessor, the Grendel P30, before, but it's been at least fifteen years, so I took Oleg up on his offer to give the current iterations a spin.
I'll be up front and admit that I still don't get the point. .22WMR is in that gray area where it's marginal as an antipersonnel round, but will turn a squirrel or rabbit inside out, making it a bit too much for hunting small game for the pot. It's obviously better on varmints than .22LR, but so are lots of things, like .22 Hornet, which is reloadable.
It's also almost as expensive as centerfire handgun ammo, which makes it less than suitable for plinking, and its operating pressures require more robust and/or sophisticated designs than the humble .22LR, as can be witnessed by the discontinuation of most straight-blowback .22 Magnum rifles here in the modern United States of Liability.
Still, a 30-round magazine does cover a multitude of sins, and both weapons were pleasant to shoot. The suppressed carbine was quietish and seemed accurate at the pistol ranges at which I was shooting, and the pistol was stupid easy to shoot: Like a Ruger MkII with a really big muzzle blast. Even going really really fast, you could keep the rounds on a pie plate. I was actually very pleasantly surprised by the trigger.
Like I said, I'm still not certain what exactly it's for, but you know what? If I had to buy a lightweight plastic pistol that fired a high-velocity smallbore cartridge of questionable utility from a large capacity magazine, I think I'd be foolish to spend twice and more the price of the Kel-Tec on an FN Five-seveN.