It probably means it’ll take longer for Nvidia to release a driver for Linux 6.6 and might stop them from doing so. They’ll probably find a way to circumvent this and continue to violate the GPLv2 the kernel is licensed under.
If your on a distro which gets a new kernel quickly it might be a good idea to pin Linux 6.5 so the system doesn’t update to a kernel which the driver doesn’t support. But whether that’s necessary woll probably be talked about more once 6.6 actually releases.
PS: If your on a 2000 series or later GPU you might actually be able to use nouveau at some point, since there’s ongoing work on an open source Vulkan driver with actually useable performance. Thanks to Nvidia it definitely won’t work on Pascal and earlier.