Why does login via social networks redirect to a new browser tab instead of using a popup?

Why does login via social networks redirect to a new browser tab instead of using a popup?

Starting from version 2.0.0, a number of security improvements has been introduced in the Social Login module in order to avoid malicious attacks. For this reason, the flow for registering and logging in via social networks has been redesigned to open a new tab when a website visitor chooses a social network. It is strongly recommended not to alter this behavior to preserve module security.