In my experience using e-ink readers (admittedly I have a Kobo, which may not be the state of the art), I would like to refresh the screen rapidly in bursts -navigating menus, flipping past an index - and then have a non-backlit screen with low power cost to show the same content for a while. In other words, a variable refresh rate.

If you think of the refresh rate not as a constant frequency but as variable with user input, there are some cases where driving eink quickly in short bursts could make sense? It seems like this project offers a foundation for such a controller, where e-reader controllers are strictly optimizing for low refresh rates. E-ink is not going to be competitive for playing a video game or watching a video, but you can create a more responsive experience with less eye strain for typical tasks like marking up documents.

Yes, that’s the mental model I’ve been working from. Variable refresh tied to user input makes a lot of sense: short bursts of speed for navigation or editing, then settling into a low-power static state.

Part of the challenge is deciding what belongs in hardware and what should sit higher up in the OS or software stack.

Hopefully, as more people get the kits and the community grows, we’ll be able to think through these questions together and explore where the right balance between hardware and software should be.

That sounds like the way to go. In terms of reading books (my normal usage of e-ink readers) you don't need 60hz when flipping a page, but it's a must when trying to use an app menu, or using Google Drive for example.

Identifying when to increase the refresh rate may be a challenge but I can see it pretty doable for this kind of "limited" scenarios where you either read or navigate a storage app.