People can take quite a few 9mm ball rounds if they don't get hit in vitals, whereas a 9mm JHP will essentially explode. Cops these days are switching to "frangibles" which are generally polymer-bonded projectiles made up of small (dust sized) BBs which act like hollow points but cannot penetrate walls (even sheetrock) because they literally explode. Some others are made of copper, which have serrations to cause fragmentation. In either case, the bullet enters, explodes inside the target, and causes incredible trauma without danger of overpenetration, exiting a wall and killing a civilian, or ricochets.
Copper:
Polymerized:
I actually keep the Glaser Blue Tips in my .40 caliber handgun at home, in my hand safe.