I read them. That's how I tell whether the editor is an idiot or not. If you can't string a coherent thought together, it's less likely that you can do so in video either. There might be idiot-savants who can put together thoughts only in visuals and not, you know, thought... but if I hear that a video is good, then I'll watch it even if the info is drivel. You can look out for clues along those lines; some people are just geared to think only in visuals and not in words/thoughts.
But in most cases, the "omg lol i maed tihs in 2 mins it tuk so long lol" factor is my major bad-video filter. It's not ironclad, but it helps.
Of course, that doesn't count if English isn't your first language. But that's easy enough to tell.
And note: a "good" description doesn't have to be long, and a short description isn't necessarily bad. The key word is coherent. Unless you're
trying to be incoherent, which is a different thing entirely.
