The basic design of TFVC is that of a centralized repository on a server with authorized clients connecting to it to exchange information. Git's distributed nature is the complete opposite, with no central authority by default and the possibility to freely push and pull changes with others. Of course, you can create a central server that harbors a copy of the Git repository that everyone agrees is the newest version. This difference can be seen in the following diagram. The Git repository can exist in a local TFS or the Azure instance, while the TFVC one can only exist in one central place:
