It's not the same sharing relationship. You have to be friends with someone before you add them to a Facebook List. Google+ has no concept of "friends". How you see someone is not necessarily how they see you.

Yes, they are, but both might be wrong answers to the question of how to share to a limited number of people.

For example if I would like to share with my colleagues I would much prefer a centrally organized group instead of everyone keeping their own "work circles" up to date (eg when new interns come and go).