That's not how Magisk works. Magisk and Xposed are NOT the same thing.
I'm fairly new to magisk, yet I already wish I had a nickel for every time this is stated in this thread. :D
Dude, compatibility is literally the first paragraph of the OP (first post).
Because it is integrated in the ROM simple.
If anything, it would be in the add-on zip. Therefore there is still an additional flash involved. Adding it to the lite build wouldn't be in everyone's best interest....
Just donate, sooner or later. It's worth it.