Don't really understand why is it such a big deal how browsers internally define the size of pixels, do they use dpi or angles (it would be more correct to say trigonometry)? It is an interesting fact that I've never before really gave a thought, but complete irrelevant to anyone but guys building the browser rendering engines. And still now you have people calling for new "better" units and what not? Why? What am I missing?
It is really helpful if you are web developer. For instance, if you need to alter some layout that was made some other units, it is good to know how the units relate to one another.
yes, sure, but this is not about that, all CSS unit have the fixed relations clearly defined. Angular pixels are just about relative scale between the size on the screen and the real-world size (whatever that would be, because a print size is again relative to the chosen dpi, so it's not an absolute measure)
