I think that re-booting is not necessary, but the thinking is changing. In
the "old days" most people had desktop computers and left them running
24/7. Now most people have laptops (not me) and re-booting is more
frequent. There has always been an advantage to re-booting in the you can
use the changes right away.

As for looking down noses at Windows users, there is still no comparison.
Windows nags are more in your face and forceful. The Ubuntu one is
discreet. Also a re-boot in Linux and Windows is not the same. when you
re-boot Windows there is a major delay on either the beginning or end, or
both as things are installed and written to the registry, then reloaded.