You have to distinguish the fake color e-ink that are used in mass consumer products which are actually black&white e-ink plus an LCD layer and are expensive, and the real color e-ink where each micro capsule embeds 3 to 5 different inks of different colors.

The latest are pretty complex devices, very slow to refresh (hence why they are not used in your e-reader) and also very expensive. But the rendering is way much nicer because it’s real ink that is used to render the colors.