Top reason was simply price and maintenance. Deploy this kind of tech to 3400 stores is seriously non-trivial (something I know, from having attempted to build and sell tech to Tesco), and even very low unit costs compound fast.

Tesco top concerns with this type of tech are:

1. Price. Tesco is very capex sensitive. They generally only want to spend money on assets that have multiple uses.

2. Will it work 100% of time, or very close to it. Incorrect price tags are a serious issue for Tesco.

3. Who fixes it when it goes wrong and how?

Again these don’t seem like hard issues, but 3400 physical store makes it hard. Especially when you can’t rely on store staff to deal with uncommon problems, they aren’t given the time or training, due to retails razor thin margins.

One of the interesting non-obvious problem Tesco had with eInk price tags was simply making sure the right product tag appeared on the right shelf in the right place. This is despite has a very competent stock management system that tracks exactly what item lives on what shelf.

With paper you just swap the tags and move on. With eInk displays you can’t do that because then physical location of a tag will no longer match it’s stored virtual location.