Never bought any payware campaigns for IL2. I've bought, IL2, Pacific Fighters, and IL2 1946, and that's it, not sure I'd pay for something done purely with the mission editor, I mean, why not just duplicate it yourself for free?
I've paid for YAP missions for WOV, because they have a lot of custom models, voices, terrain and weapons, so that is worth it in my opinion.
Similarly, I bought the ARMA Queen's Gambit add-on because you get a DC-3 in it, and some other stuff, which could not be done with simply ARMA's (very cool) mission creator utility. But if it was only missions I could have created myself, there's no way I'd have got it.

Chock