I am convinced that the more ways and styles a game offers, the better. I have no problem killing the world boss on both maps myself. But if I want to unwind after work, I’ll happily watch my thrall do it while I stay in movie mode. Why not?
And on the Savage Wilds map and in mods like EEWA, killing high bosses alone is unrealistic.
But I do not like the authority perk because it is more difficult to evaluate warriors: as a follower, he shows some abilities, as a guard - others. I may forget that he is weakened on guard.