I think the op was trying to say the main appeal was the fanservice and sex which isn't wrong, like genuinely would you have read this manga if it didn't have those elements? And if you would why would you read it over Record of Ragnarok (a series that have actual stakes plus a majority of other things that reinforces its formula) or Rosen Garten Saga (a series that also has stakes, character development for its cast, consistently solid writing, etc.)
This manga is just a power fantasy that's made clear in the very first battle when Mikigami won because of plot. If you're into that, all the power to you (I personally read this because the art is cool) but RoR and RGS are definitely not comparable to this series.