ProgramData is for admin stuff and things that need to be shared between users. AppData is for personalized settings per user. For example, AnyDesk stores the unattended access password in ProgramData, as well as the ID. Sure they do get copied to AppData when AnyDesk runs on boot/login on any user, but you could also have some user specific options (like language) and they get stored in a separate file in AppData.