I think I've heard that it's implemented as a library because we're not sure about the best way to implement the concurrency stuff. It's easier to experiment in a library than in the core.
Right, yeah, maybe I read that it's something like the typing system putting constraints on direct interop, I'm not sure.
I mostly follow from the sidelines, having a deeper buyin with Elixir, but whenever I find the time and a use case I'll build something in Gleam and learn more.