+Vincent Jan Latzko
Your eyes can resolve much higher resolutions than this, most of the time up to 2400dpi. But you don't need such high resolution for everything – images look nice already at ~360 dpi (Apple Retina or the Moto G display), while Text strains your eyes extremely if it's printed with less than 1200dpi (that's also the reason why you'll print text always with at least 1200dpi).
So you won't be able to see a direct difference, but your eyes will be strained less and it will feel just smoother. I compared the screens of Nexus 4 and Nexus 5 and even though you can only see the difference while looking closely, the screen of the nexus 5 just feels more smooth, the text is easier to read and it just strains the eyes less.
But you're right, screens with more than 360dpi are not necessary, they just provide minor improvements.
But then again you could also walk around all day in T-Shirt and shorts, but you'd still buy a suit in real life.