That's true, but that issue isn't specific to CSS inches. Pixels aren't pixels, points aren't points, etc.
It's not even an HTML/browser issue. There's a general problem with knowing in software the real-life physical size or length of something displayed on screen. The calibration information available isn't generally reliable, though I think people are paying more attention these days with the growing interest in AR.
It's not even an HTML/browser issue. There's a general problem with knowing in software the real-life physical size or length of something displayed on screen. The calibration information available isn't generally reliable, though I think people are paying more attention these days with the growing interest in AR.