I think the Mini gained popularity when the AR still had a spotty reputation for reliability. And yes the ergos do suit some people more than the AR.
I had one in the early 90's that would put 5 in an inch at 100 yards. I wasn't smart enough to keep it, unfortunately. I've also got Dad's 180 series, which has the super-skinny barrel. I've never run it seriously, but if it will shoot 3 or 5 accurately from a cold barrel, that's plenty good for a predator rifle. It will get some use, for sentimental reasons if nothing else.
Not everybody is free to pick what they want for rifles, so in those cases the Mini isn't a bad option. But except for artificial constraints the AR will do just about everything better.
One thing I noticed when I had a Ruger .44 carbine; those silly slick plastic buttplates that Ruger used for years on Minis, .22's, and .44 - play hell with accuracy; the gun slides around on your shoulder when firing. A rubber buttplate is much superior.
