Why mount a folder to a folder in fstab?
Solution 1:
Yes you are right. Fstab record
/home/ubuntu/stuff /home/bob/things auto defaults,nofail,nobootwait,bind 0 2
is analogous to the command issued from your shell:
mount --bind /home/ubuntu/stuff /home/bob/things
It means that you can access ubuntu/staff content from bob/things folder.
You can read about differences between symbolic link and bind mount here: https://askubuntu.com/questions/557733/ln-s-vs-mount-bind