The information tends to be of lower quality (despite the love). For example, I wanted to know why left and right bicycle pedals are threaded differently. Three youtubers gave reasons that I could tell didn't quite make sense. But Sheldon Brown's website explained it ("precession"). https://www.sheldonbrown.com/pedals.html

Looks like he added this detail later - it's easier to increase the quality of information like this with text, than with video.

Some people add VO later (jarring); Khan Academy re-does videos (breaking references between, confusingly). Most youtubers don't do either.

Videos often have paid product placement, unacknowledged. It's very effective promotion, because it feels grass-roots.