My wife, who is a paid Dropbox user, recently installed Dropbox on a laptop running the latest version of macOS. She's currently working on a group of Word documents on her iMac. Most of them are not visible on the laptop. If we head to the Dropbox website, all of them are there, but have a faded out symbol with the legend "this file is hidden from your device". They can be downloaded to the downloads folder, but that defeats the whole purpose of Dropbox.