Well "Yesterday's Enterprise" was an alternate reality episode, as for the "Inner Light" isn't that more it's just a dream episode?
It occurred to me only after I posted that indeed, Yesterday's Enterprise has real stakes, if you imagine a separate time line that could collapse our own. We survive and Picard et al are friends with the Klingons, but the timeline that Yar leaves goes on and the Federation collapses.
They all could be alternate reality episodes for all we know when we watch them first. Of course, TNG wouldn't play tricks on us like that, Yar died for real after all. But for the course of the episode, it would be nice to suspend belief.