The girls are indeed hot. Yeah, they wear very discreet clothes aside Mitsuri and some others, but their designs scream to be lewded.
Or you're telling me that Daki or Hinatsuru/Makio/Suma aren't attractive? These four bitches have amazing bodies and tits.
The Spider Demon mom too.
Nezuko is retarded so people like to draw porn of her. Shinobu personality makes her attractive to lewd. Mitsuru needs no further explanation.