- some games change with updates (try to play destiny 2 red war story line with your physical disc that you can still buy for some reason despite game being free)

- Nintendo can block specific cartridges (only thing that step Xbox and PS from doing that now is that it's not implemented on their end)

- some games have separate online pass and/or DLC codes that can only activated once

- on PC CDs used to come with a cd-key you had to activate (still do?)

- See Xbox One 2013 DRM plan

Only way to "own" a game is to have a pirated version of a game regardless of a platform.