Honestly, I don't know why people would be freaking out about this. This technology is nothing new and Walmart and Korger aren't the first stores to use this. I highly doubt that prices would change in real-time right in front of a customer. If it did, it would be most likely caused by someone hacking the system.
In general, I am fine with this technology. I recall my retail days when a team of co-workers would have to go around the whole store updating price tags and strips. It's a lot of paper.
I don't recall the battery life span of one of this digital price tags. Hopefully the system tells them if one of them are low. It would be a pain having to patrol and make sure they are still working.