I'd go further than saying "doing actions against an id is a shortcut". I say it's an antipattern. Ids should only ever exist at the edge of your system: When y

I'd go further than saying "doing actions against an id is a shortcut". I say it's an antipattern. Ids should only ever exist at the edge of your system: When you're taking serialized data in and turning it into objects, or you're taking objects and turning them into serialized data out. That serialization should be handled completely separately from your application logic; you shouldn't see (non-opaque) ids in your application logic.