He's 19! There's a difference.
He is learning to play in the NHL. He is too good for the AHL. There's no point for him being in the there, better he gets the growing pains out of the way now because, in case people aren't aware, the Sharks still suck. This is not a playoff contender. Sure if they were, he should earn his spot but, as it is, he is being counted as a major piece of the future. This season is a learning curve for him. If he's not doing what you want him to be doing at this level, this is why you keep playing him. He needs reps.
I think the reason that some are looking at him under a microscope is because Mack came in as that guy. Smith isn't at his level and it's apparent but he can play.