Why is Dropbox listed among "Apps Using iCloud Drive" in macOS Sonoma?

I have recently noticed something weird. This MacBook Pro I now have is new, M3 Max (14-30), 16-inch, so I documented every step of its configuration. In System Settings > Apple ID > iCloud > Apps Using iCloud, the starting list after the first boot contains 15 apps. Looking at the list now I have 22—which is irrelevant—but one of them is Dropbox, with the switch turned ON. Why on Earth would Dropbox need to use iCloud Drive? Shouldn't it be its own thing? I have turned the switch OFF for now, and Dropbox is still working fine, as expected, but something else strange happened: Time Machine backups are no longer completing. Browsing the log I could find several repeated entries pointing at something starting with com.dropbox.somethingElse and about the auto-backup starting but then always finding a reason not to complete. The UI in System Settings (as well as the menu bar) showed "Preparing to back up", and stayed there for the whole night. I forced the MBP to shut down, waited a bit, then booted in Safe Mode and successfully completed the backup there. Browsing the log again with the T2M2 & Mints apps showed 2 backups in the last 24h which had completed successfully, so I wonder what made it get stuck.