Agree with this.
I think both Smith and Koskinen have their limitations. Smith is also prone to some very weak goals, often of his own doing... but he's also more competitive than Koskinen and more vocal. He holds himself and his team to a high standard and that's what makes him a leader on this team. Smith is an alpha-type goalie who demands as much of you as he does himself, with plenty of frank and personal accountability to go around.
My sense is that Koskinen, while also competitive, is much more beta in the sense that he'll do his best to prop you up, even when you make a mistake you won't hear about it, he'll bear that cross on his own. I don't think that's particularly helpful for the Oilers given where they are AND given Koskinen's own struggles. I think there are a lot of times where Koskinen lets in a goal that is completely not his fault, entirely on the D, and nothing gets said about it. Koskinen lets them off the hook, they can blame their weak goalie and not improve. Whereas Smith will still tell you (as a D, Forward) what you could have done to make his life easier, while still accepting his own mistake on the play.
It's a fine balance, and when you lose that balance, you lose trust.