That's an unfair criticism. Kindles and their eInk setup provide the perfect low-fi hacking experience that developers love. It's minimal, slow and barebones linux base makes it easier to hack für such fun projects.
Well I'm a hacker too and I don't really prefer low-fi hacking experiences, or at least not that flavor. I prefer getting stuff done since my free time after work is limited.
Oh and I used to work with eink displays for a living, but they always end up gathering dust for my hobby projects because it's only good for very few niche use cases that most of the time are better served by the more flexible and practical available solutions, unless of course, your uses case is showing it off on the internet for clout because this time what makes it special is it uses eink even though it adds no benefit.