Our Individual plans are designed for one-person accounts. The Individual plans include unlimited devices once you enable 2-factor authentication. If you don't, then it's limited to 6 devices.
Our Family plans support up to 5 total users, each with their own logins and unlimited devices.
The reason we do this is to support every user having their own account. While we understand that sharing accounts and passwords is very easy, it's not the most secure sharing solution. To combat this problem, we offer affordable family plans where every user can have their own username and password, along with unlimited devices.