I'm not even sure why we refer to logical pixels (a.k.a. CSS pixels, etc.) anymore, for exactly the reason you mentioned. We should be saying things like "this

I'm not even sure why we refer to logical pixels (a.k.a. CSS pixels, etc.) anymore, for exactly the reason you mentioned. We should be saying things like "this only needs to be 512px x 512px because it's never rendered larger than two degrees of viewing angle" or something to that effect. But I guess that's hard to think about... ems could be a good compromise.