The advantages of splitting /bin and /usr/bin, and /sbin and /usr/sbin outweigh the disadvantages

[kindusmith <meiguozhichun@gmail.com>]

1. First, root and ordinary users will not be able to use commands in 
each other's directories, which will greatly increase their security

2. If /usr is partitioned separately instead of a unified / partition, 
ordinary users can also use commands in /usr/bin, which increases 
convenience

Of course, these advantages have become impossible now with the merging 
of directories