As I understand it, the idea of this project is to build a microkernel and associated systems that might compete as an alternative to the Linux kernel.
This would allow things like, more elegant hot patching of the kernel, formal verification of core parts of the kernel, better hardware enforced isolation of different systems for security. I guess also some people like the idea of a GPL3 kernel against tivoisation.
I can see why someone might adopt a mature version of this for say, a safety or security critical system. Trouble is, until it is mature and battle tested, its not a good bet for those things. And without adoption, it's not gonna mature or get used.
A fringe operating system can drive innovation by taking risks that a mainstream OS would never. Ultimately any improvements will appear on main stream operating systems so even if it's never used we're going to see some benefits.