Safari is a webkit browser, off of which Chromium/Blink is a fork. So, it's not really a point in favor of real diversity on the web.

non-chromium browsers only matter if the owner in question actually has any incentive to give users more control. Apple exercises even tighter control over their software than Google.

Firefox matters not because it's "not chromium" but because it's firefox, a non-profit dedicated to an open web.