It's "cool" but in terms of usability I think it's terrible. I would think that someone who works full time as a designer and has strong opinions on right and wrong would think twice about wasting screen real estate on mobile devices with a bunch of bullshit like a sticky menu, footer and comically huge "window"-headers.

The only thing I see is the design equivalent of over-engineering a car with bells and whistles that nobody gives a shit about, it's simply showing off and sending a signal to other designers, which is obviously fine if that's what you're going for, but personally I hate it (as you may suspect, my job is not in design).