I'm author of a rust based task manager (not (yet) FLOSS, unfortunately), where we needed "pluggable task sources" (jira, github, trello, etc).

In our setup, the "sources" are more like configuration. Whereas the core, the business logic, is more like code.

Typically, one would configure with e.g. YAML. As we can see in many projects, that have a DSL, in yaml (k9s, GitHub actions, ansible, etc). But, rather than inventing another DSL in yaml, we realized we do need some logic, something very poorly expressed in yaml. And we went for Lua.

Long story to say: if your config typically has some logic in it, it makes sense to go for an embedded scripting language to provide it, rather than building it into the core domain, or to invent yet-another-yaml-amalgation (yayamla?)