A more apt comparison would be with film reviewers. Before the internet, knowing what a movie was about, if you didn’t care about spoilers, would require either someone watching and telling you, or reading a piece on a newspaper (or, in some places, watching TV). It’s almost the same with “professional” game reviews and how they completely lost space to random dudes on the internet.

Also, watching a video usually feels more like entertainment, whereas reading a review or walkthrough feels more like doing some research.