Well, it makes it much harder to build the system from a simple assembler.

Guix is AFAIK the only distro with a well-paved bootstrap path from a simple assembler to a fully-working distro[0]. Adding the JVM or even GraalVM (which is what Babashka is based on) makes the bootstrapping that much harder.

[0]: https://guix.gnu.org/en/blog/2023/the-full-source-bootstrap-...