I use a hydrometer before I pitch yeast, when I rack, and when I bottle. I think these are very appropriate times to use one. I never decide to bottle until about two weeks after the bubbles stop. I take gravities to know ABV%.
I think the root of what Janx is saying is that new brewers sometimes get kind of insane about hydrometer readings and don't pay attention to what really matters: is the yeast done working? I've seen a lot of posts where people freak out about hydro readings and they don't say anything about the beer bubbling, or yeast sediment, or taste, or anything else that could tell you just as much without doing a lot of unnecessary math.
Use the hydrometer, but don't rely on it, and don't use it when it's not appropriate.