Nonetheless, the more forks, the better. I think Chromebooks are great.
Another reason is that it is very difficult to use ChromeOS is China. It is the same for ChromiumOS.
Chinese internet is not very reliable (see http://www.nexedi.com/NXD-Internet.China). We needed reliable network. So we embedded in NayuOS a technology called Grandenet (http://www.grandenet.cn/) that provides IPv6 wherever we are.
This way, we can reliably connect to our company servers when we travel.
Also, we thought that it would be useful to have a local git command line, because we could not find any good web equivalents for this particular tool (Gitlab or Github are nice for reviewing code, but command line is required for rebasing and cleaning up the repository).
On Chromium OS derivatives, there is a "guest" mode, which is not linked to any Google account and is like a browser "Private Browsing" (Firefox) or "Incognito mode" (Chrom*).
There is no way to add custom packages on Chrome OS (and we don't want to use Chrome OS because of privacy issue anyway).
We also share the binary images for some Chromebooks (not all right now, sorry). This is not the case for Chromium OS, that you have to build yourself.
(By the way, npm is not available right now).