Micro/angle dependent Roughness & Iridescence

Yes - at glancing angles. Take a look at some of the other practical examples posted earlier in the thread.

essentially if you have a material that looks diffuse because it has a very fine microstructured surface, like the back of an iphone 7, and view it at a very shallow angle, it starts to show very sharp, almost mirror like reflections.

This effect can be seen in many real world materials. Just in my office now I can see the effect on the side of our printer, the back of our tea tray, my phone etc. Basically any material with a very fine grained surface will show this to a greater or lesser degree.