In practice, my companies have done them less frequently. Kernel packages are less often about security patches and more often around a magic combination of kernel+GPU driver+software--I think one of them paid Red Hat for custom cuts.
As for maintaining a personal machine, that distro would probably suggest rebooting more often than RHEL (you'd also have to effectively logout/"restart" for any core package for your Desktop Environment or X). I haven't measured, but I feel like my Synology gets updated every few months.
As for the impact of rebooting. Windows Updates (and macOS updates) are more than just a reboot. It's often an unknown amount of time. Even for a normal reboot, it's really really nice to just leave everything open so you can pick up where you left off. Personal or work it's more than just a browser, but terminals I have open, shell history, vim sessions.
It's like a recent article about fast software https://craigmod.com/essays/fast_software/
Fair enugh, but depending on what distro you run that seems to be fairly often as well. Like, more than 'a few times' a year.
Then again if you dont run a server for which downtime is a true loss, or something alike, is rebooting that much of a problem (honest question)?