Because it might save you a trip to the workplace on an evening,
weekend, or holiday sometime.
fallback-reboot is a last resort, when you have a wedged system that
you'd like to reboot remotely. It requires that the machine be
pingable, but it does not require that machine's hard disk be
functional, nor does it require fork() or exec*() to be working.
In theory at least, it should not require paging or swapping to be
working either
fallback-reboot reboots the machine hard - it makes no
attempt to sync your disks. That's because fallback-reboot assumes that
you've already tried all the methods of doing an orderly shutdown you
can think of, and fallback-reboot is all that's left to try, short of
hoofing over to the machine or calling someone on the phone..
fallback-reboot currently only supports Linux, Solaris, AIX, and
FreeBSD
but adding support for other operating systems would most likely be
fairly trivial as long as you have an mlockall function or
something similar, and you can figure out how to get your system
to reboot without syncing or exec'ing.