Writing your own scripting language is really not something game developers should be doing for the past decade or so. There are so many good off-the-shelf options ranging from Lua to C#, plus a litany of obscure (but good!) ones.
For performance-critical code, even a tiny DSL is not a solution I like unless you're transpiling to C++ or something.
Hooking LUA or similar can introduce a lot of unwanted complexity, be harder for an untrained implementation team member to understand, and be less of an exact fit to the purpose. There are other cases where it makes sense though.
For performance-critical code, even a tiny DSL is not a solution I like unless you're transpiling to C++ or something.