If the secondary user is a different person than the primary user, the secondary user should purchase it's own license. Behind your QGO account, there are your personal games profiles/optimizations and your folders where you organized your apps and games. So if another person uses also your QGO account, he will override your data and the next time you will want to install QGO you will see that your data have been modified.
1 QGO license = 1 user because of that