IMO, its probably because CVA promotes pellets and powerbelts. Demand from shooters is likely what prompted the BH209 plug. I do agree though, it wouldn't cost much to include a BP tool with each gun - whether you need it or not.
Knight and TC plugs work well with any type of powder, CVA you have to modify or purchase.
I don't own a CVA, but my thought is they are decent rifles for the money (especially the lower end models) and they typically shoot well. But imo I think that rather than being on the cheap and spending years trying to gimmick coatings and treatments, they should just use a quality stainless steel. And partnering up with a decent scope company would probably be a better idea, unless they own Konus which wouldn't surprise me. Who buys a Konus, unless it came on a CVA?
Ok, rant over. Sorry. I'll stick to my Knights.