Eh, when I'm browsing bitcointalk my schedule isn't usually that busy--but I'm not the type of merit source who sifts through threads looking for posts to merit (though I will if I come across any).  It would drive me nuts if I clicked on random threads simply to check for meritable posts, for the reason you said, which is that the good ones are in a many-layered sandwich of shitposts.  I've had enough of that to last a lifetime.

Having a job kind of implies that you're getting paid to do something, and being a merit source is a volunteer position.  Actually some merit sources like myself didn't even volunteer.  At some point in 2019, Theymos just sent out a PM to I don't know how many members telling them that they were now merit sources and to go forth and do good for the forum. 

The merit sources that are the most "generous" are the ones who believe in the system and want it to work (and I put myself in that category).  It's supposed to impede the progress of shitposters, account farmers, and the like.  But it's also the mechanism by which members who contribute positively to the forum achieve higher ranks, and if there wasn't a lot of merit being spread around, nobody would be ranking up (and thus it would make the merit system strictly punitive).  I sure don't want it to be that way, so I try to be generous. 

I remember the days before merits and how bad the shitposting problem was, so I appreciate how it's cut the account farmers and a lot of the zero-value members off at the knees.