There's benefit that comes with the family account. I use one with wife and kids. You get shared address books and easy read/write access to others' folders you can configure as needed. So I have a folder in my IMAP tree that my wife can read (for bills etc.) and we both have read access to the kids' accounts. And we all share a family address book that I update once for everyone's benefit. In my experience, a family account is more than just a couple of individual accounts under one billing mechanism - it has technical advantages as well.
