Yeah, I’m surprised that security wasn’t mentioned at all. The Linux kernel’s BPF JIT is incredibly restrictive on what it can interpret and produce: presumably a JIT like this would be much less constrained.
But in a sense, security is just part of the engineering required to make such a project a reality. No one is going to be deploying a kernel like this until it's proven, so perhaps the emphasis on security isn't needed for an initial blog post.