I mean sure if you don't mind the fact that ESLs tend to have horrible resolution. The chroma 74 you linked, for example, only displays 640x384 for a 7.4" panel. Good pick if they work for your application.
thanks to lack of very rough pixel boundaries, eInk looks quite goods even at that res, actually. Photos looks perfectly fine, eg: http://dmitry.gr/images/chromaGrey.jpg
Depends on your viewing distance. If viewed from a few feet / a meter, that resolution is probably enough. The contrast ratio might be the bigger problem. From a low-effort search, photo paper has a contrast ratio of 100:1, while e-paper has a contrast ratio of only 12:1. Photos displayed on e-paper are going to look washed out.
If you want to hack it and don't want to pay for consumer grade quality for neither hardware nor software, then the device you linked is a good choice.
e-Ink price tags are designed to be used and abused by store public who do not care about store property. They are built like tanks, so "consumer-grade quality" would in fact be a downgrade...