@WouterJ the way the form functions are implemented means that the named arguments don't work with them (they are using custom nodes, so they would have to implement the support in these nodes). On the other hand, these functions are using the Twig built-in nodes, so they support named argument.
So for forms, using the right argument is impossible (as there is not even such names as it does not map directly to a function but processes the arguments IIRC) whereas it adds some value here