Looks like it's more suitable for making games, since it "uses its own high-performance rendering engine to draw widgets" -- non-games typically don't reinvent widgets.
Kai's power tools were a fantastic experiment in visual UI design. I'm left wondering why games are the only brand of software where ui innovation "is ok".
In the case of custom GUI elements sometimes things don't need fixing. The audio industry always makes control panels etc. look different to the common UI and this is one area you still see it.
But for the most part, having a consistent UI means the system is easier to use. I wouldn't want my fork mutating every time I had a different meal, in the interests of innovation.
The meal is a good analogy. For prolonged activity a local minima of utility that is 'good enough' can be achieved. This would correspond with a single app.
The fork, however, is not necessarily the best tool for 3D modeling, composing music or some new entirely new activity.
The fork is basically a GUI element, eg. a button.
Buttons appearing to be anything but buttons is as useful as a fork being shaped like a playing card - it isn't useful at all, and I could not easily shovel food into my fat face with aplomb.
I am not saying that custom GUI controls/widgets shouldn't be invented where needed, just that the basics being reinvented just for the sake of reinvention is unnecessary, and confusing.
Since last year, Google's iOS apps have gradually adopted more and more elements of Material Design, including the color palette, the app bar menu, the MD iconset, the floating action button. And they typically remain best in class; it turns out that Material Design works well on iOS too.
(Note Google's implementation is not necessarily consistent--just look at the different button tap effects for Calendar vs. YouTube on iOS. Sigh.)
We've also borrowed MD concepts for the iOS version of our new app (https://recent.io/) without user complaints.
Ugh, no thanks. Please keep the low information density, searing color blocks with white text, FAB covering content, drop shadows, and overdone animation away.
I view the YouTube iOS app as a good example of the direction Material Design is headed; it's even dropped the hamburger menu, which was a big part of the original spec.