#1: This is fantastic from a conceptual perspective! Focus on simple computing tasks that are important, without distractions, ads etc. Open source, kit, looks well-designed.

#2: I've programmed and used those EPD displays (The same model used here I believe specifically). They are neither a joy to program, or use. The programming is much more complicated than a normal display because of how you manage refreshes: Partial, full, when to do each etc. The latter because, as you can see in the video, the latency is high.

I think responsivity and latency are one of the most important things for a pleasant user experience. We as engineers and developers have failed at this in general over the past ~2 decades. I think a device like this that breaks conventions is in a nice spot to also break this trend. Especially not using an OS (Or using an RTOS?), there should be no perceptible latency, if he changes to a normal display. I could tolerate a display like this for some uses and like a static sensor that runs on battery, but for an interactive device like this? No.