It's really cool work the folks at CloudFlare are working on. The trade-off there though is that it's still a process isolated by the OS and so relies on OS-level security via the use of syscalls. Even if context-switching is reduced with Deno, making privileged calls to, say for instance `open()` or `socket()`, still impose wasted CPU cycles as the OS checks whether the process is allowed to perform this action. With unikernels, the call is allowed (and no extra CPU cycles / instructions are called) since the unikernel is its own VM and is isolated by physical hardware separation.