As someone who looks up tutorials on various pieces of software, the dislike ratio was a pretty good indicator as to whether or not a particular video would help me do what the title of it says without me having to sit or scrub through the whole thing

Just a counter opinion, I find them fairly useful. Not 100% useful, but more often then not very useful.

Thanks to the idea of disliking as a meme, the ratings are essentially meaningless. An overwhelmingly disliked video is probably worth watching, if for the humor alone.