The Pebble display isn't e-ink, or unique amongst watches, it's an off-the-shelf MIP LCD from Sharp.

You can get the same thing in watches from Garmin, Coros, Polar, Suunto, Casio and probably more.

I think you're confusing Pebble with something else. All current models on the website as well as the OG pebble (according to Wikipedia) use eink displays.

https://en.wikipedia.org/wiki/Pebble_(watch)#Hardware

> The watch featured a 32-millimetre (1.26 in) 144 × 168 pixel black and white memory LCD using an ultra low-power "transflective LCD" manufactured by Sharp

Later generations are color, but it's the same tech. If you've ever used actual e-ink then it should be obvious enough that the Pebble displays are something else, it would be nowhere near responsive enough to keep up with pebbleOS's animations.

They’re Sharp memory displays, functionally LCDs but with memory for retention under each pixel. They are not and have never been eink.