How is the battery life on the Pimoroni? I've used RPi Picos before, and I love working with them, but IIRC they are comparatively power-hungry, even in deep sleep.

Power consumption of the Inky Frames in deep sleep is minimal as power to the Pico is cut completely. An RTC is kept powered to wake up the Pico on a schedule, or pressing any button will wake up the board too.

Haven’t tested this particular one but using the badger eink display has been a blast. Super low power — you can run that one off of a lithium coin cell battery. You can control when it wakes. I presume this one will draw more with a larger color screen and wireless, but again you can control when and how it wakes to balance power draw vs. more frequent updates.

Why aren't there any CMYK screens?

Because its not print. Only print nerds love CMYK.

It’s a valid question because colors from an emitting light source use RGB whereas reflective would make sense to use CMYK. As a practical example a 4 color CMYK eink display may look better than or at least equal to the 7 color display above.

The frustrating twist is that - under the hood - this screen is CMYK. There’s a magenta “ink”, which would fill out a huge gap in the colour gamut, that we can’t even use. The same applies to cyan. Both colours are fundamental to the display tech and yet poorly represented in the very boring 7-colour palette.