What's The Point Of Domestic Servitude In Modern Stellaris.

I just tried the Pleasure Seekers civic for the first time and tried using mostly Domestic Servitude slaves. All that happened was I ended up with like a hundred pop spread across my worlds not doing anything other then producing amenities, which turned out to be worthless because apparently the happiness bonus you get from having high amenities caps at 20% at around about 100 amenities or something. I was ending up with 200-300 amenities per planet.

I checked out some posts on this reddit about the subject that all said Domestic Servitude is really good, but they're all older posts from before city district's determined building slots and they all said Domestic Servitude was good primarily for getting easy max building slots via pop.

So in modern Stellaris what's the point of Domestic Servitude?