Even back in the Windows 3.1 or 95 days I didn’t have to reboot this often - sometimes twice a day. Seems a bit excessive?
After applying an update you need to make sure anything using the unmatched code is replaced by the patched code. A reliable way to do that is a reboot. Actually a reboot is pretty much the only reliable way to do that.
So I am not surprised that a distribution targeting end users asks for a reboot.