That's fair. Although it's linguistically silly, I think it's fair to delineate casual/dedicated like it's done in other mediums. "Bookworm" & "Cinephile" are useful and don't sound like they were concocted in a Mountain Dew corporate meeting.
"Bookworm" and "cinephile" sound like appropriated insults, whereas in contrast "hardcore gamer" sounds like one thinks more highly of themselves than of others. Maybe that's what gamers need: an insult to appropriate.