We require a Google Account for our users to login, simply for authentication purposes. Google has been working on the security of Google Accounts for over 10 years, combating hacking on a daily basis. It has one of the most secure authentication mechanism in the industry (more secure than most banks).
It also supports two steps authentication, with a large number of options (SMS, mobile app on most brands of smartphones, recovery passcodes…). Adding to that the number of corporations that have recently leaked hashed passwords (LinkedIn, Twitter, Yahoo, eHarmony, last.fm, …), we feel that users shouldn’t have to trust one more party with their passwords.
We don’t send any data to Google, nor do we ask permissions to access more data than the name of the person and their email address, so there is no compromise.
People who already have a Google account and don’t mind using it (the case of most people) have one less password to remember and one less account to secure. For people who don’t have a Google account, or don’t want to use the one they already own, they can easily create a new one, with fake personal information, and use it to access Predictious.