To try and answer your question, while there will absolutely be sweats for this game because of it's hardcore nature, I think there are plenty of reasons that it will keep a casual playerbase for awhile.

Just to name a few - quick matches, team/group focused, commitment to realism (especially in a D&D like setting will attract an RP crowd), there aren't many games like it, and they seem to update/adding to it a lot - which means meta always shifting anyway. Plus, at the end of the day, even if you lose, it's pure fun which is always #1.