More discussion on BGG :
https://boardgamegeek.com/blogpost/114436/asmodee-group-acquires-board-game-arena-analysis
Personally, I see these online games as marketing tools for physical product, not just for online games themselves. A BGG'er mentions how sales of physical product increase after the online version is release. I think that makes sense. An online game lets you "try before you buy" and can be useful to learn the game and make an informed decision for purchasing.
That doesn't, of course, mean
TTS isn't under threat, and some games will no longer be available. Just because someone owns a property doesn't mean they know what's best for it!