This is just personal opinion, no more. I am not a rifle stockmaker, though I have made them, and am mostly just a rifle and shotgun shooter. But, it seems to me that many classic rifle stockers want(ed) to include a cheekpiece. When a cheekpiece is included on a stock it offsets the eye. The only way to get the eye back to the bore line/sight line is to build in cast off. It works, as you said, in tandem with a cheekpiece, because one offsets the other. I don't really understand the purpose of a cheekpiece, myself, except for aesthetics. I have rifles that work perfectly with open sights that have no cheekpiece, or cast.
As long as my eye aligns with the sights, without physical contortions, I don't care if the stock has a cheek piece or not. I really believe cheekpieces are mostly about aesthetics. But, that's just my opinion.
