TLDR: use main language of the project to write scripts.
+1
+2
:)
Additional couple of remarks:
- at some moment you can think about writing tests;
- at some moment you need to reuse something else from the project (also it's possible to duplicate\reimplement something from the project using scripting language);
- at some moment you can think about integrating functionality implemented inside the script to the main project (admin endpoint\UI\background job\etc).
That's why it's better to write additional logic not using a script but using the main language from the very beginning.
p.s. scripts are nice only for the interactive context, but as soon as you save it once, you've created significant tech debt