Re: But why?
>> For google to claim it can do better is arrogant.
Not true, Linux is pretty bloated for many applications, particularly embedded ones. In practice it needs a CPU with MMU support, which can be large and expensive.
Also this is Google so this is just another one of their releases to have the world dog-food their alpha releases.
In other news, google announces that Fuschia has been cancelled. "It was just an experiment"
But the need for a light weight alternative to linux is a real one. In my opinion, this is what is holding back Wear OS/Tizen for eg. Linux is a poor choice for power sensitive battery operated applications like that. All the other vendors for smartwatches and fitness trackers do not use a Linux based OS.
A POSIX compatible alternative could technically serve the open standards you mention.