The idea is simple – allow for shared email addresses within Duo/Family plans, which anyone in the family group can access. Allow for true shared documents/folders in Drive, that anyone who they are shared with has equal access – at the moment, shared folders cannot be accessed through Finder (macOS), nor made available offline. To attach a file from a shared folder, the sharee must first download it from the web app, which makes a mockery of using cloud storage in the first place.

It seems that Duo/Family is really just a pricing tool, not a shared family group in any meaningful way.