Sure, except that it didn’t actually work as designed in my case.. my user got loads of errors when trying to participate in the forum by email right after joining. Luckily she perservered and complained to me.
It is confusing to have groups that I can add via one interface but not via another. I guess I have to separate in my mind the system groups from the admin-created groups even though they are managed together in the same place as though they are the same thing.