Hello, king casual here, I think I’ve done 1 M0 in BFA though I’m not entirely sure, 0 M+, 0 raids though I did 2 bosses in LFR because they drop recipes 
Forgot, I have no idea what it takes to get any essence besides the ones people always complain about because idc, I don’t do visions or 8.3 assaults or anything in 8.3 really and I don’t wear much corrupted gear because I’m not doing cloak unlocks on 59 characters 
I don’t care about the power gap because I’m a full time collector 
So if you’re my kind of casual then yes there’s a reason to play I’m generally always in content older than the current xpac.
When I was a raider I always did this New raid coming out? Time to watch TankSpot or Fatboss videos, read guides on EJ, analyze logs of guilds who’ve cleared the bosses my guild hasn’t gotten to yet.