Real regexes (actually regular…) are infinitely better than Python code matching the same string (if they are sufficient) - you can compute their intersection, union, complement; check if they can match anything at all (and generate an example automaticallly).
For software builds, Bazel and others use Starlark, which is a restricted Python subset, so builds can be guaranteed finite and can be reasoned about.
Ansible may or may not offer any benefits in return for the limits (I am not an ansible guru), but in general, most tasks do not need a Turing complete configuration/specification language - and it is then better to NOT have Turing completeness.