Shallow color gradients (e.g. blue sky or anime) result in visible banding on 8bpc displays, which is a large fraction of displays. Ordered dithering is GPU-friendly, so it's useful to reduce higher-bpc content to those display formats without introducing banding.

Light sources in video games and such. If you have a light source with a very large falloff range illuminating a large area, you'll have noticable steps in the gradient.

Ordered dithering is a very cheap solution to this.

Lots of sensors these days will give you 10 or 12 bits of data per color channel. You may want ordered dithering when previewing on an 8 bit display.

Yep e-ink is a good practical use. In fact any system with black and white display use ordered dithering when they want to draw images