[2019] Why are the gear sets locked behind the raid in the first place?

Honestly this bother me, the best to get what was intentionally "good" sets to help your team do the raid... is proving they don't need them. That honestly seems like a backwards way to do them, look i'm not talking about eagle bearer so don't go around throwing that argument around about exclusivity of raid rewards in normal. As far as i am aware the only gear set that is considered good is Aces & Eights, while the rest go from meh to trash, so whats the point of making them artificially rare? If they were strong like eagle bearer we could be arguing about harder content giving better rewards, but if thats not the case why lock the gear sets made for raid when you don't need them to beat the raid?

This was something they literally commented in the first game, how people would grind incursions in the first game for gear set where the people that already proved they could complete the incursions, and instead create a weird sherpa situation