In my opinion the only real reasons to use a pistol cartridge of any caliber in a rifle is for cost savings, short barrel performance, and subsequent suppressed use.
1.) 147 grain subsonics could be had for ~$0.22 per in 9mm, 115 grain supers are now in the ~$0.18 range. Really the only cheaper is .22 rimfire.
2.) 9mm performs well in 4.5"-5.5" inch barrels, which takes a suppressed package to ~12"-14", the length where most rifle cartridges start unsuppressed, save the
.300BO at 7.5" and ~$0.55 per round and up. I never understood the appeal of a 16" 9mm AR.
Neither of my 9mm SBR's have any appreciable muzzle rise or recoil, they are more accurate than i can shoot them, and they have been enjoyed by all who have shot them. Reliability has not been a factor, although they tend to prefer to not be soaking wet with lube. The increased cost per round of the two above calibers, to me, offset any perceived benefit.
That said; toys are fun, and you've only got one life to do what makes you happy. If its your thing, go for it.
