What do juniors at MM FSG groups actually do?

I understand that MM sponsors groups are responsible for institutionalizing and maintaining relationships with PE fund decision makers (and at BB doing relationship backed lending), that frequently have former coverage MDs from BB banks that come to MM shop to relax a little bit on the back ends of their career, but what do analysts in these groups do? 

I have heard wildly different things-- they make the same amount of comp as a banker in a traditional coverage group for a fraction of the hours worked, sometimes they do modeling and sit with the sector teams, while other times they can be glorified executive assistants. It sounds like the type of gig where you have to be a total self starter or risk not learning anything-- is this true?

Not really sure what to make of this group and opportunities for juniors, besides direct exits to PE, some to small HF, and others to larger FSG groups at BB banks?

Can someone provide some clarity? Any insight is appreciated.