I only really worked in an office for a very short period of time that had fax machines but I remember the big problem with them was that you knew you had received something but no one could find the piece of paper. Or the reverse, you'd sent someone something and now you couldn't find the document you sent, so then they had to send you the scan that you sent them. Which meant you had to phone them to get them to do it.

As boring as email is, if something has been sent or received you can always just pull it up again.

I'm pretty sure at one point we even printed out emails so the admin person, who was old and refused to adapt, could keep using the old filing system.