A hotfix driver is basically an out-of-band update designed to solve a specific issue or multiple issues. You really only to need to install them if the issue(s) in the release notes apply to you. Otherwise, you can hang tight and wait for the next regular driver update, which will bundle the same fix(es) into it anyway. They could also see improvements by the time they’re packaged into a regular driver release.
“The GeForce hotfix driver is our way to trying to get some of these fixes out to you more quickly. These drivers are basically the same as the previous released version, with a small number of additional targeted fixes. The fixes that make it in are based in part on your feedback in the Driver Feedback threads and partly on how realistic it is for us to quickly address them,” NVIDIA explains.
“These fixes (and many more) will be incorporated into the next official driver release, at which time the hotfix driver will be taken down. To be sure, these hotfix drivers are beta, optional and provided as-is. They are run through a much abbreviated QA process. The sole reason they exist is to get fixes out to you more quickly,” NVIDIA adds.