I'm a casual NTR consumer. I've enjoyed the lewds thus far and think the game is pretty awesome.
That being said, I've got a save where Sana is super lewd and one where I actually did grind out to get to Act 3 and avoided what seemed to be avoidable corruption (Anon getting poisoned still results in Feif snatching Sana). Is there any point to keeping her lewd level low or are these options just a time waster? Is there a better potential ending for Anon and Sana if she doesn't cheat (as much)? More scenes? Etc.