Personally, I'm not a fan of shot or frangible rounds in a carry handgun for a private-citizen CHL.
Like stroo, I'll try to avoid hyperbole, and I'll also state up-front that I haven't searched the Net to find other opinions on other gun boards. So I may be uselessly repeating stuff...but what's new?
The fact is there are no Leatherman tool or Swiss Army Knife equivalents in firearms. A Leatherman folder can fit in your pocket and ingeniously contain pliers, tweezers, a few cutting blades, flat and Philips screwdrivers, etc. One handy tool for many jobs. Pretty cool.
Firearms aren't like that. They are more complex mechanisms, and they have to be larger than a Swiss Army Knife to do their jobs effectively. (Don't take me to task here: I'm purposely discounting .22 derringers and such.)
IMHO, every private citizen who is legally entitled to do so should own at least three firearms: a rifle, a shotgun, and a handgun. Multiples of same would help the firearms industry, and will afford you many options of desired
fit-for-purpose use.
A carry handgun is like Forest Gump's box of chocolates: you never know what you'll get...meaning, this is the one firearm you have on you at all times, and you'll never know what situation you'll find yourself in.
A carry handgun is a small, defensive weapon. And it must be available to handle, potentially, a pretty wide spectrum of attacks. Most carry handgun loads--assuming you don't carry a .500 S&W Magnum in an 8-inch barrel--are fairly anemic compared to many rifle cartridges or a 12-gauge slug. I'll even admit that my preferred .45 ACP +P comes up lacking.
But a carry handgun is not a Leatherman. A handgun is one device, one tool, one function...and you have to decide how best to be prepared to use it across the multitude of scenarios in which it might be employed.
My point here is that a shot-loaded pistol round might be the perfect load if a VCA reaches into your driver's-side car window and tries to extract you from the vehicle. Three-foot head-shot with .45 Magsafe, and he will probably cease the attack.
What if you're up against three drawn guns at 5 to 15 yards? What if you have to take a shot at 20 yards or more? What if you have to take a head shot?
What if you have to take a hostage shot?
Even at extreme CQB range when my offhand is gettin' up close and personal with the attacker's face, I want a round that can penetrate and break bone, not just cause a wide, shallow wound. The latter may eventually disable him, but my objective at bad-breath distance is to fracture the pelvis or the acetabulem and disable the attacker's movement. Your typical meth-head may not be immediately impressed by devastating soft-tissue injury.
I keep quality HP defensive rounds in my handguns. They're best-suited for 98% of what I might encounter.
Disclaimer: I am not an expert. But I've trained with some who are.