system members, when to use, when to avoid?

what's the lowdown with system members? when should you use them, when should you avoid them?   currently I'm creating and storing these values as attributes in the object. “owner” seems like a weird term. Owner is “created by” if I am right?   just a bit confused why and when to use these vs modeling it out (also in the domain model you get to see the association lines, which can be helpful)   Edit: Owner on NPE temporary attributes seem like it might make sense?
1 answers
0 → Please look at this document.