It should be used for billboard advertising. You don't even need that many PPI pixels per square inch because of how high above it is, and it would save ginormous bucks on printing canvases and technicians changing the ad. Not to mention, timed advertising.
When i read this comment i had to go look at the product because i was expecting 10-20k. Looks very reasonable to me. The most expensive is only $2500? and the cheapest only $600? Seems super inline with what I would expect to pay for art.
Also, with e.g. an oil painting on canvas, the cost of producing that is the time of the artist to paint it by hand. I don't think 10-20K is anywhere reasonable for e.g. a mass-produced inkjet-printed thing. Likewise 10-20K for a PNG file would be even more insane.
https://www.waveshare.com/product/13.3inch-e-paper-hat-plus-...
I just went through the process and made this for myself: https://www.printables.com/model/1189455-waveshare-133e-6-co...
The total price was around $420. This includes shipping, taxes (to Belgium), a pi zero w2, a sd card, and printing a case.
Are you happy with the quality?
Compared to the previous gen e-ink (7-color ACeP), the contrast and the colors are so much better. I also have a bunch of 3-color (black/white/red) panels - video and more pictures on https://frameos.net/ ) - and the contrast is similar, but the colors are obviously limited.
So yeah, I'm definitely happy.