https://wccftech.com/dropbox-for-mac-beta-adds-desktop-and-documents-folder-syncing-like-icloud/

The latest beta for Dropbox for Mac has added support for desktop, documents and downloads folder syncing. This works similar to how iCloud desktop and documents syncing works, which means that you do not have to move your existing files and folders to a new location under the root Dropbox folder.

Apple's iCloud has allowed users to sync their desktop and documents folders to the cloud for some time now. The files in these folders are automatically synced to all devices where the user is signed in with their iCloud ID, including iPhone, iPad and other Macs. The new Dropbox beta feature offers the same functionality.