The share button inside YouTube is unlike the icon used in virtually every other Android app. Rather than the usual set of three connected dots, we see a horizontally flipped version of the reply symbol in Gmail. Well, Google isn't yet changing the iconography, but it does seem to be testing out a new location.
In addition to the share button's usual home at the top-right corner of a video, we're also seeing it next to the like and dislike buttons.
If you're not seeing the new layout, try closing the YouTube app and opening it again. That works for some users. Though, it's not like this is a change that's as YouTube's experimental web player.
As for whether this makes sharing any more intuitive, I don't know. But for the time being, it's pretty redundant.