Unlike fridge remote control (note, not remote monitoring but remote control) e-ink price tags actually make a good deal of sense. The prices are already managed centrally so it reduces the labor to needing to accurately document which piece of hardware is at which shelf location as opposed to needing to manually check that each tag has the up to date price. (TBF OCR is now good enough and mobile SoCs now powerful enough that you could probably automate most of the traditional task but that wasn't historically the case.)