E-ink displays are very popular among users of e-readers thanks to their extreme resemblance to real paper. One of their advantages is the extremely low power consumption, as they only draw power when they change what is displayed.
There are disadvantages as well. Firstly, there is no backlight so using it in the dark is a no go. Also, their refresh rate is rather slow and they are B&W rather than color displays. Such displays are on all of Kindle e-readers as well as in Sony e-readers, the two big players in the ebook market. Also, there is a company that used it on a smartphone as a secondary display. It is Yotaphone and it became relatively successful.
Vernee Thor E: E-ink screen ? pic.twitter.com/Sha8vHgiJJ
— Jorker Lee (@jorkerlee) May 1, 2017
Now, there is a serious rumor accompanied by a photo and a short video as you can see above, that Vernee will put such a display on Thor E, that will be launched in May with and unknown price so far. The video is a bit blurry and the photo could just show a smartphone in B&W mode rather than a e-ink display, so we would take it with a pinch of salt until we have more information.