The have one offseason job - to prepare for the combine and make a good showing - just to hold their potential draft position. if you can't even do that, maybe you shouldn't be in the league - I'm talking to you mr Rams practice squad edge rusher.
Years ago - bad GM's used crazy good combine results to draft some guys too high. Mike Mamula anyone?
Seems like those days are over. I do think the core reason the combine continues as is - is because it's another 'event' for the league in their off-season calendar. Gotta keep the money machine rolling