HQV is not a calibration DVD. It is merely a test for processing performance and mainly how well it detects cadences. Obviously you generally can't do anything about this besidess buying a different processor after assessing any weaknesses in your system. There are the patterns for noise which may be handy if you are exploring noise reduction systems, but in my opinion it is of greater interest to view a variety of content and see the impacts on that content. Noise reduction necessarily will end up sacrificing some detail in the image, depending on how good or bad it is. It's more interesting to do A/B testing on a wide variety of content, not just the couple clips on the HQV disc, though they are interesting to examine the reduction of actual noise. But they don't really help that much see how much non-noise is being lost too.
So basically, I recommend it highly if you have a need to assess processor performance. But if you do not, then unless you like having lots of test discs, it likely would not be useful to the average user. If you already have your system assembled, there is really nothing proactive you can accomplish with it unless there are various processor settings and you are unclear as to what they do. Often this is the case, some devices will have a setting for say movie, video 1, video 2 or something like that and it isn't clear what each is doing and how they deal with cadences. In that situation something like HQV is very useful.