I hop into PF for Ex/ Savage for fun. 0 chest late week practice/ clear parties. I get nothing out of it except free practice and... yes, fun.
Especially after unlock I tend to live in PF. Before that it's a bit difficult to get into parties because most want 2 chest, some even as late as on Mondays and I'm locked out of them but still possible and if a party that lets me join catches my eye I hop in on whichever class I feel like playing and have fun beating a boss into submission.
Doing it for the shinies alone feels unrewarding and unsatisfying because gear doesn't is useless for the most part unless you're going for the most current ultimate. If the gameplay part alone doesn't appeal to you then I wouldn't recommend doing savage because the ilvl increase is fairly small for the time investment. Not to mention you can get good gear with sometimes suboptimal substats from Tomes + Alli raid/ Nut coins alone.