The only real difference between an SBR and an ar pistol is one youre legally allowed to put on your shoulder and one you're not
There are substantial ergonomic differences, and practical accuracy would be seriously affected by free-handing an awkward pistol vs. a SBR or carbine. See, I'm after the *why* that's related to the pistol or your use of it, not just its legal positioning. If there's something in the legality that appeals to you, then explain so I can understand. For instance: "I'm not supposed to have X, and that makes me want to have X.y because it's thumbing my nose at a silly law." Ok!
I'm not trying to be a jerk, truly. I optimize for utility (in my context) or precision in my shooting/firearm choices. It's where I started - smallbore competition, and later NRA bullseye pistol before moving to IDPA and hunting. So I'm curious to understand why people make different choices that seem strange to me. I know my priorities and context are not the only ones (see JWB), and everybody has their own for their own reasons.
Here, I'm being pesky without offering up my own version of this. Let me remedy that:
My version of 'impractical' is a Ruger Blackhawk Flattop .357. Too big for a concealed carry pistol, useless for most competitions (better choices for CAS, which I don't do anyway), poor choice for SD handgun if possible to choose otherwise. But I LOOOOVE it. I love the aesthetic, I love the operation, I love the little western fantasy that comes with it. My goal for that pistol is to be able to reliably take a deer at 50yd. Will I ever? Not in any planned fashion, my .54 Hawken, .30-30, and 20ga are all better choices, and I don't live in a pistol hunting state. It's the pistol I would WANT to have on my hip walking into the woods for a month... Will I ever do that? No. Is it really the best choice for that? Meh. But ballistically it makes a lot of sense: 4-5/8" barrel on a .357, and I prefer to run 180gr XTP's at 1000fps. So it's subsonic with the muzzle energy of a .40S&W, but with better downrange trajectory and penetration - all at lower pressures, so much more friendly recoil. So it's fun to shoot at the range, and pretty darn accurate as a range toy. I don't mind shooting slow because I prefer precision (see above), and because ammo is expensive either in cash or in my reloading time.