[chrismorgan]

This argument is unsound: CSS already takes that into account. All of the units (px, pt, mm, in, &c.) are, for screens, defined in terms of a reference pixel, which is the visual angle of one pixel on a device with a device pixel density of 96dpi and a distance from the reader of an arm’s length. https://www.w3.org/TR/css-values-4/#absolute-lengths has some more explanation and diagrams that demonstrate what’s going on.

No, the reason why it’s customary to boost the font-size a little on larger screens is because otherwise things start to look silly because you’re using such a tiny part of the space available to you, and you have a larger viewport, so you can increase the size a bit without losing too much from the screen at any time. But if you take it too far, it starts to look silly for different reasons, because it’s unreasonably large (and more importantly, inconsistent with common practice).

(Also: 16px = 12pt.)