A lot of things have lua bindings and a lua interface. But once you stop being your own boss, your control over which interfaces and bindings to use shrinks drastically.
I believe the question was more: What fields/industries are actually USING the lua interface by default? Where would being able to say "I am very experienced with lua scripting" be a particularly strong asset.
I agree that in any organization if the choice of use a tool is not in your hands you are forced to use something else well, that don't have anything to relate with lua or with any other programming language.
That's a people problem you accepted when hired, but can move to other happy place that used lua or python, or ... etc (=
This is not true at all. Where I work we use OpenResty in places for a WAF but we don't touch Lua for anything else. You don't need to know much Lua for this.
Using something as an embedded language is a little different than building standalone systems/infrastructure projects with something.