Most video guides just show you the mechanics of the fight and they all try to explain to the best of their understanding of the mechanic. The video guides are there to help you prepare for the fight so that you know what's coming up and what to do in that situation. However, they are not substitutes for actual experience for the encounter and can only take you so far. Personally, the video guides help with those who have problems visualising the battle from a written guide. It's all on preference. Some prefer to learn by watching, and some prefer to learn by reading. All in all, I think it's wrong to say that video guides are bad. They are informative just as written guides to some extent.