Sony know their box has to fit in with every room. They can't be too outrageous, meaning the options are black, grey, or white. Grey hasn't been popular for CE devices since the 90s. White is in but doesn't suit every room. Black works everywhere. Ergo, it's black, only to be differentiated by trimming, highlights, and lights, for exactly the same reasons PS2 was black, PS3 was black, and PS4 is black. I also expect matte because people don't like the finger-prints showing up on glossy surfaces as happened with PS3 - makes it look worn in a way a matte finish never does.