On the game engine side, probably not a lot until there's more ecosystem built up, but across the board you could look at the niches filled by the Java/Groovy and C/Lua pairings to get a pretty good sense of what's possible— it would be the tools stuff that would most excite me: build/CI/automation frameworks, that kind of thing.

Alternatively, look at a project like ruff— hundreds of linter rules statically implemented in native Rust [1], maybe that would make more sense if the rules could be more tersely expressed as runtime-loadable roto scripts that have access to the Python AST and a toolkit of Rust-supplied functions for manipulating and inspecting it?

[1]: https://github.com/astral-sh/ruff/tree/main/crates/ruff_lint...