Much like Android, Chromebooks are considered a different target even though they use the Linux kernel. This release will be for a generic Linux desktop binary rather than specific 1st party systems.
Sure, and when I worked at Google on Chromecast there was also that build of Chromium.
All of that is very different from The G actually providing a packaged official Chrome build, though. Which for some reason they couldn't be bothered to do before (Firefox exists though)