Doesn't "Nia" mean "Non-Interesting Addition" ?
As far as I can see, it's just a 6 inch e-reader with a front-light, 8GB RAM, running the latest Kobo firmware. The only people for whom the Nia would be an upgrade, are those who are now using a 6 inch Kobo without a front-light and less storage, and want to upgrade one or the other, or both.
For all others, the Nia is just another e-reader; an iteration where the front-light and 8GB storage has trickled down to the cheapest Kobo models. I don't expect it to be special, or to have any serious flaws.