Seiko Epson's 500ppi 3D display for phones: how dense is dense enough?

Not that we're complaining, it's just that human eyes usually can't discern denser than 300ppi, and few interfaces are built to take advantage of... ah, who are we kidding? This is awesome. Seiko Epson has built a 2.57-inch 3D display for phones that runs at an astounding XGA resolution, and should be ready for commercial applications in two years. There's a special lenticular lens on top of the pixels to allow you to view images from multiple angles, which usually means a hit to the pixel density, but obviously this display can handle a bit of that.