Okay, so I looked it up a bit, but found nothing relevant. I got that, for example, keys bought on this site won't work with modules from Steam, and so on.
But I have another question:
I already have several modules (FC3, A10C...), all of them were bought on Steam, and successfully activated.
Now if I want to buy a new module, but this time not from Steam, but from DCS site (it has a nice sale offer this two days), will it work with Steam modules? If I, say, install it somewhere on steamapps/common/../DCS.., and run DCS World from Steam, will it "see" modules bought from DCS site? Will I be able to play?
Or steam modules are steam modules, DCS site modules are DCS site modules, and they are incompatible with each other?