To be able to do administrative tasks on CUPS (creating/modifying/removing queues, changing server settings, deleting someone else’s jobs, …) out of a Snap, independent which type of app (GUI, CLI, daemon, …) one has to plug cups-control, and NOT cups. The cups interface allows only listing printers, options, and jobs, printing jobs. and deleting one’s own jobs. Therefore cups-control is a “dangerous” interface which needs manual connection or permission of the Snap Store team for auto-connection, in contrary to cups being a “safe” interface which just auto-connects.
Note also that the command line tool lpinfo, even being totally read-only, is an administrative tool and its operations (list available devices, list available drivers) are considered administrative and therefore you need to plug cups-control to use this tool or do its operations via CUPS API or equivalent IPP requests to the CUPS daemon out of a Snap.
If you see a non-administrartive operation getting blocked or any operation from a classically installed tool or application, this is a bug, please report it.