Battery powered or thermally constrained devices.

...which are playing back video, so they're likely blowing most of their power budget on the display and on radio. I guess my threshold of "amazing" is different. Again, I'm not denying some incremental utility in specialized uses, but most of the time, it just doesn't seem to be worth the pain - especially since nothing about the implementation will be portable or maintainable in the long haul.

In the same vein, no one is writing a smartwatch software stack in 100% bare-metal assembly, although in the hands of a capable developer, I'm sure it could prolong battery life.