It looks interesting. Node.js still needs a good full-stack web framework that just works out of the box and is extensible, like Rails in Ruby. Would love to see some demo of an app written in it.
My initial though was: "Oh! This lets me quickly build a repo that merges all the smaller repos using git submodules!"
And then I see, it doesn't do it, it just merges the repos...
Why would you do that?
Honestly, I don't know why for years git submodules have had such a bad fame. It works out of the box. You can checkout subrepos but you don't have to if you don't want to. You can set up separate branches, have separate commits, CI/CD workflows for each of the repos.
AND you're still able to have all the monorepo advantages: to lock down the dependencies to an exact version; to let a dev/CI pull all of them at one go.
Why wouldn't you just use git submodules for that?