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IMO it's much worse. It's slower, less knowledge-dense and you can't jump around and learn the things you need the way you like. Reading and re-reading is a feature IMO, not a bug, and videos have all the drawbacks of sitting in the classroom without providing any of the benefits (you can't, say, ask the video for clarification).

If the medium is visual (knitting, a sport, etc) then video is great. But a math lecture is probably better as text, with images/diagrams.

How often are videos remade to fix poor examples? How often is text fixed? (Where's the ever improving video version of Wikipedia?)

This is true <in person>, when you have confidence that the presenter is of high quality and on target. It's not true generally, because in reality the needle/haystack problem. Line of sight is better for parralel processing than serial/ sequential a/v.