I moved from Kindle to Kobo for the sole reason that the backlight had tunable color temperature. I've ended up liking it for lot of reasons, including how open they are.
Kindle Paperwhite (and possibly others) have adjustable colour temperature too, with time-based automation. From a quick squizz, not quite the same as the Kobo (I don't think it has the "more blue in daytime" function) but just noting that it does exist on some in some fashion.
It's great that Paperwhite have caught up to Kobo in this manner. Back when I was evaluating replacing my (lost) Kindle I believe it was only an option on the top tier ($300+) Kindle.