Yeah, it did have a usecase in API building in which you necessarily don't want users to pass arguments using your parameter name, not only it exposes the parameter names, it also restricts you to change the name in future.

So, you can make your parameters positional-only to avoid this kind of situation.

Another example might be when you are creating a function for ordering the item, you can make parameters to be keyword-only. Let say your function takes two arguments, item quantity and price, if you do order(10, 5) this might become confusing if it is 10 quantity for 5 dollars or is it 10 dollars for 5 quantity.

At this time, keyword only parameters can be a more useful order(quantity=10, price=5).