The intent for eTransmit is to copy a Revit model (worksharing or standalone file) and other dependent files to a single folder for internet transmission. Using it like uploading a Revit file to different consultants (say Structural and MEP) for coordination will be very useful.
Lately, I have been asked by several new team members and they want to know what's the best way to archive some Revit files (For major milestone or design changes, we usually save a copy and date it). I immediately thought of using eTransmit is a better way to go. Compared to the traditional process of creating a detach model and save it as a new central file; if you have more than one model, you have to do it one after another. It is just tedious.
eTransmit setup is so easy and intuitive to use, you can choose to include other Revit linked models as well as .dwg linked files or even keynote (.txt) file as part of the transmit. The setup will also DETACH the Revit file during the process. In other words, this makes it perfect for archiving.
One suggestion though is I would go through a purge unused process before using eTransmit. Doing so would result a leaner file for archive purpose.