They tend to stay in a tight formation and not spread out nearly as much as buckshot, negating most of a shotguns tactical advantage. They are much more like a slug.
They also tend to overpenetrate and could hit bystanders.
I wouldn't carry a shotgun loaded with them, but I would keep some on hand in case you had to deal with someone in body armor.
At home, I do load them. My bedroom is on the second floor, so I will be shooting down and don't have to worry about overpenetration. Since I know the house and the range is short, I can be confident of hitting my target even with the small pattern.
There are too many home invasion robbers now with body armor and even Police or FBI Raid Jackets.
So9
Correction to you and others. They were good at penetrating previous generations of body armor. Modern body armor is designed to stop a 7.62mm rifle shell at point blank range, and still retain the ability to do it again.
790.31 Armor-piercing or exploding ammunition or dragon's breath shotgun shells, bolo shells, or flechette shells prohibited.