When you say "weird" you mean "different from mainstream languages", but the exact way in which your language is weird (declarative data description/transformation) is probably exactly where languages will be going in the future because of how well-suited they are for LLM reading and writing. Those languages expose the structure of the computation directly such as data shapes and the relationships that transform them, rather than burying intent inside control flow.

With more explicit types and dataflow information, the model doesn't need to simulate execution (something LLMs are particularly bad at) as much as recognize and extend a transformation graph (something LLMs are particularly good at). So it's probably just that your particularly weird language is particularly well-adapted to LLM technology.