There is also a similar case for /usr/bin vs /bin (e.g. some OSs
traditionally had very stripped down versions of a few command in
/sbin or /bin, then fuller ones in /usr/bin - trivial example would be
"vi" of course).
This is because /sbin was for 'static' binaries (static-bin). We needed this back
when live CDs didn't exist, or if you somehow foobared your GNU libc you had /sbin/sln
(static link) to fix a system, now a days you pop in a CD, chroot to the saddened Linux
system and repair it easily. You used /sbin as your emergency kit and superuser tools.
Shawn.