Whilst a lot of people say 'download from the manufacturer's site' I'd say its not always obvious where these drivers are on many manufacturers sites, and novice users run the risk of also downloading from sites that pertain to have the drivers but are actually malware sites, or downloading the wrong driver.
Driver update tools (if they are good) ensure that you get the right driver and from the right source, something also novice users might not do. For example, Iobit's Driver Booster ensures only drivers that have passed Microsoft's WHQL tests are downloaded (something that if you download from say Intel's site might not be true as initially they do not), so reducing the chance of incompatibilities. I'd disagree therefore and say for novice user's they do have a use, for more experienced users, commenters are probably right - its better to get from source, but to say they have no value, is I think incorrect. Up-to-date drivers can make a difference, and in some cases fix security and performance issues, so are important, just like updating your windows O/S.
I use Iobit's Driver Booster and have never encountered issues of incompatibility. I use the tool mainly for convenience, it informs me when a newer driver comes out, and saves me having to play 'hunt the driver'. I could do it myself, but why bother when there is a tool to do it for me.
There are a lot of bad driver updates tools out there, as there are a lot of PC optimser tools too, but to say that they are all useless I think is a over generalisation
