Even points are a lie now. I open a PDF on my computer, and the PDF viewer might scale it to fit the window, and the OS might scale it based on my preferences,

Even points are a lie now. I open a PDF on my computer, and the PDF viewer might scale it to fit the window, and the OS might scale it based on my preferences, and maybe my monitor is a projector which means the OS has no idea how big the viewing area actually is.