Elvis is a DAM based on a folder structure with its own permissions for viewing content, downloading, editing, editing metadata, deleting files, etc. Every user has their own private zone that they have full control over, within the boundaries of the capabilities assigned to them. So in some parts of the folder structure you may be able to download files and edit them, while in another parts you are only allowed to see previews.
These permissions are additional to user capabilities. Every user has a set of capabilities that allow access to specific functionality, for example a download capability or an export capability. These control which buttons and menus are available. It is possible that you have the download capability assigned to you, but if a file is in a folder where you only have preview permissions, you will not be able to download the original file.