The Files area is your private online storage space and is associated solely with your TurboSquid member account. Only you have access to this area and it is here you can store whatever important files you would like; documents, family photos, works-in-progress, etc. You get 1GB of free storage for your Files araa and can request more should you need it.
By comparison, Workspaces are collaborative areas where you invite multiple other users to share files and ideas to complete a specific task or project. You also get 1GB of free storage for all files in each workspace and can request more for the group should you need it. However, it should be noted that files here are not simply private files, they can be viewed by anyone you have invited to be part of the workgroup, so keep private work in your Files space, and work that you want to share in the Workspaces area.