Considering you can only choose Chinami as a threesome option if you decided to see her naked in the bathtub, i'd bet you'll have to follow a chain of flags to unlock wizard content: first Akira sees Chinami naked, then chooses her as the threesome partner, then ahother one and so one. So you get to the wizard content only after you have been a committed degenerate. And yes, it will be wizard content, people hoping for a time skip are being a tad optimistic imo.
As how it will affect the story... not sure, I mean it's not a small deal to just let it pass like nothing when others characters (Chika, Touka) eventually find about it, but at the same time, probably Sel doesn't want to let it divert too much from the main path, since it would be inconvenient to write. What I would like is that it leads to a bad end, an early game over. Not saying Selebus will go there, but I'd like if we can have several bad endings in the dark path, finding new ways to get Sensei (and maybe others) killed, having sex with wizards being one of them. I'm most likely wrong though.
.. 
