The server version has the ability to act as a web server - you can use a browser to view and manage DT databases. It was there in the older DT Pro Office. In DT3 it’s been updated with better access control. It’s the only difference between the Server edition and Pro. I guess the intended use case is to give access to large groups of people to DT content without having to but large numbers of licences.
The beta is the Server Edition, so has everything.
Don’t know about scanning and email archiving - the product comparison page doesn’t seem to refer to the non-Pro edition