How is this better than using rkt with an lkvm stage1[1], which also uses the work done by the Clear Containers team? It looks like Kata packages QEMU as well, which seems a bit overkill.
[1]https://coreos.com/rkt/docs/latest/running-kvm-stage1.html
[1]https://coreos.com/rkt/docs/latest/running-kvm-stage1.html
They also said the same about Xen, that a special purpose microkernel was a better choice than Linux as a hypervisor...
Xen was successful because it was innovative, and because it worked around the fact that x86 was not virtualizable at the time. But after ten years of healthy competition, the only reason to prefer Xen to KVM would be things like QubesOS.