Mozilla hates their core users. They think that things like this will attract "trendie" and "diverse" users, which is a futile endeavor. "Trendie" people are always jumping from trend to trend, so even if they switch, they will just switch away when the new trend comes along. "Diverse" people use what ever panders to their race or sexuality the most, and Google panders to them far more than Mozilla ever could.
Maybe when Mozilla finally kicks the bucket in a few years, someone will start something else that isn't just a Chrome fork.