> I don't understand how such high PPI really matter at all.
If there's more resolution than the display (or the observer's eye) can support, the extra resolution can be used to make diagonal lines look better (as one example), through a sophisticated drawing method that eliminates jaggies. I'm not saying this is always true, but it's on the list of options to exploit the extra resolution.
> I mean it increases battery usage, it costs more, and all you get is smoother text and smoother pictures on a less than 5 inch screen.
That's pretty much it. But consider that people who buy Apple phones know they're not buying the least expensive, most cost-effective devices, so maybe they expect to get something not present in the bargain phones, like resolution that no one can possibly notice. Sort of like having a refrigerator whose light stays on when the door is closed.
If there's more resolution than the display (or the observer's eye) can support, the extra resolution can be used to make diagonal lines look better (as one example), through a sophisticated drawing method that eliminates jaggies. I'm not saying this is always true, but it's on the list of options to exploit the extra resolution.
> I mean it increases battery usage, it costs more, and all you get is smoother text and smoother pictures on a less than 5 inch screen.
That's pretty much it. But consider that people who buy Apple phones know they're not buying the least expensive, most cost-effective devices, so maybe they expect to get something not present in the bargain phones, like resolution that no one can possibly notice. Sort of like having a refrigerator whose light stays on when the door is closed.