With editing a page in Mediawiki most people will save
their document
at sane times during their editing, such as after making changes to a
section or when the entire edit is completed.
Within something like Excel, document saving is a little bit less
sane. People are in the habit of pressing CTRL-S after everytime that
they make any sort of minor change. This can make reading the diffs
difficult.
Ah, OK, now I understand :) so, one small advantage of FTP is that the
save process can be relatively slow so it may lead users to save less
frequently :D