Not from my experience. If you use a registry cleaner, it will allow for fragmentation just as a disk cleaner would allow. Using a registry defrag tool will close the gaps and enable the system to retrieve information for the registry a lot easier and faster, thus increasing system speed. Though it may only be a tiny increase, some people would still appreciate the little boost in speed. Also, I do a lot of testing for programs that are in beta development so with all of the install/uninstall that I do, my registry needs a good clean and defrag. I'm sure I am not the only one who has need for this feature.