Yep, I know the coolwallet, and I know people like it for being thin.
I don't like to say negative things about other products, and you won't hear anything bad about Trezor, Keepkey and the like because I really think they're good products.
However with coolwallet, this is a seriously flawed design. They offer security options which completely defy the purpose of a hardware wallet: as a user, you need to check the amount and destination address of an outgoing transaction on the wallet. With a screen as tiny as they have, that's not really practical (for the destination address), so they pretty much left this option out by default.
Our goal was to have a clear, reasonably sized screen. As for batteries, we have chosen batteries that are available everywhere (AAA), and we aim for a runtime of 1-2 years. Yes you can make that thing very thin with a LiPo cell, but then you'll have to recharge every week. We think that's not practical.
I do not deny your design, but if you want to carry it, a little smaller is better.
Your product is really great.