"It's very different.
When you sit a player because he can't hit lefties, you generally start one of your bench players in his place. When Edmonds takes a day off at random, you can't start anyone in his place, so you end up with zeros.
Of course it is different, but I think to a large degree, it isn't fundamentally THAT different. You jsut mentally don't think of it that way. Say you sit blalock against lefties. Good policy right? Well, how many times did your fill-in get an 0fer? Probably a fair amount of time.
Well, I know blalock is an extreme case. BUT, most people draft their positions based upon the year's total production. So if you play the start and sit game too much with someone like blalock, you are shaving off 15 runs, 8 home runs, and 19 rbi. he becomes a 65 run, 17hr, 73 rbi player. Not too special. And think about this across the spectrum.
My point is that there are "lost" stats all over the place in fantasy baseball. And the practical effect is if Edmunds outproduces most other outfielders in 20 less games, what is the difference? You are just perceiving a lost opportunity, because it is more visible to you. But his yearly stats are still an advantage. It sucks that his days off are hard to predict, but there you go.
I'll take him.