Why atreus

In the Inspiration section. It stated that Atreus took inspiration from the various keyboard.

Is there any such detailed reason why you go with Atreus instead of using an existing keyboard? Maybe something such as this kyria annoucement, it contains the cons of the previous keyboard he used.

Also, I don't find the information in http://atreus.technomancy.us/ and http://atreus.technomancy.us/faq

Thanks.