Earlier quoted context omitted.
IMHO, these are important features. It seems it does not have Bluetooth (for a keyboard and/or headset to listen to mp3 while reading) and the battery can not be easily replaced.
Because its meant as an pen and paper replacement. Nothing more, nothing less. Besides why would you want to listen to MP3s on such a device? Your smartphone with bluetooth and microphone jack is way better equiped for such a thing.
I used mine for years after having it shipped from China (the only place I found to buy one, which meant I had to learn enough Chinese to order and to navigate the menus to change the language) until the cloud sync shut down and I couldn't be bothered to sync it manually with very outdated sync software.
There's a market for a B+W ereader with a pen. Not a big market, but there is.
-edit: however, that price puts me out of the market for this... the Eee Note cost me $200 which was perfect. $600 puts it just out of iPad Pro territory, which is where I'd personally go for that money. Shame. Hopefully it sells well enough that they can recoup development costs and bring the price down for later adopters.