If you don't you're missing valuable information/laughs. The related video may be -
the trailer linking to the full version
the original mix of the posted song
another video in the series of videos edited for time
another video by the same person

I don't even scroll past the last comment.

Can you imagine if two related videos were positioned on both sides of the main submission? It really is about layout and design choices because sometimes I'm sure it throws up useful videos.

But the more tenuously related links might deter people from considering them.

Voting for this poll ended with the majority of users voting It's extremely rare for me to watch them.