From what I've seen, .22LR FMJs out of a pistol are most certainly deadly, the issue is that rimfire cartridges are inherently less reliable than centerfire, (even if modern premium .22LR is extremely reliable) semiautomatic .22LR pistols are often finicky with ammo, and the margin for error using .22LR is substantially higher.

I myself used to carry a Walther PPK/S-22 loaded with 40gr CCI Mini Mag, but that was before I was knowledgeable about handguns, and within a year I had upgraded to .380 ACP. Nowadays, I carry .40 S&W.

That being said, this makes a lot of sense from a marketing standpoint, as there are a lot of folks with arthritis and such who cannot shoot handguns chambered in more conventional self-defense cartridges, as well as folks who are just plain afraid of guns and the .22LR looks less threatening to them, which makes the difference between them going unarmed and armed with something.
Besides, nobody wants to get shot, save for maybe the Crackerjack Boys, but they're often either on a suger high or otherwise in withdrawal and thus their chemical addiction to sweet caramel corn and peanuts overrides their self-preservation instinct, ergo most folks will retreat the moment a gun is drawn, much less been shot with one. Plus, if this Federal Punch .22LR truly is capable of 1070fps out of a 2" barrel, then it's essentially .22WMR in a shorter case, and .22WMR is comparable to .380 ACP out of a short barrel, so this may actually be a viable option for self-defense.

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Shooting Comfort is bilateral.