Interesting.
I am not sure why those statements were mentioned. I have done enough upgrades, and never went with this approach.
May be you need to send a note to him asking for the reasons.
in my opinion, you can take file based backup of the files, treating them as another file, like a .dll or program file, which will allow you to restore the system, in case of a system (I mean the Windows system) failure, you can restore the system.
Assuming that you need to take some precautions, you need to stop the SQL Server instance and perform a file backup.
I still believe that you should not restore them unless you have a crash.
Cheers,
Prithiviraj Kulasingham
http://preethiviraj.blogspot.com/