Originally Posted by zelda_pinwheel
it seems weird to me to use any kind of "physical" measurements (pts, mm, etc.) for digital media even if it can work, but that's probably just my own little neurosis.
I know what you mean, but in this case it's probably the right thing to do - the margin is there to give a little gap between the edge of the display and the start of the text to cope with slight mis-alignments, shadows from bezels, etc. This probably needs to be the same (small) amount whatever size of display, or size of text.