Font readability is the function of familiarity with the given font. So if the user clicks that checkbox to disable thirdparty fonts in the browser and use a fa

Font readability is the function of familiarity with the given font. So if the user clicks that checkbox to disable thirdparty fonts in the browser and use a familiar font everywhere, I think the user is right. :) That's why I disable thirdparty fonts by default and bug our designers when some text overflows in our app, due to some fixed width assumption in CSS, because system native font they did not design for is wider.