Going beyond 330ish ppi is actually a downgrade, especially if you like gaming.
It doesn't improve the sharpness by a noticeable amount, but on the other hand it does put more constraints on the device to drive all those extra pixels, which means worse battery life and worse performance (especially 3D intensive games).
And if that wasn't enough, because the resolution is so high you then need actual content in that native resolution, otherwise it's pointless and actually looks worse than on a lower res screen, and since there's almost no content in more than 1080p you do the math.
It's a downgrade, just a marketing gimmick.