@Soulfox -- another advantage is that a lot of these digital copiers can be set up to receive faxes digitally and not print them unless requested by a user. This cuts down on wasted paper and ink due to junk faxes coming through the printer.
Here's another advantage when using one for faxes. Some of them simply take faxes and post them to a network so they can be accessed and viewed by any computer with access to that network. In those cases, the fax might not have to be printed at all. That cuts down even more on paper and ink usage.