If mathematical utterances express propositions about formal systems without privileging any particular interpretation, they function as schemata implicitly generalizing over abstract structures satisfying those schemata
The upshot is that mathematics in general becomes metamathematics, a contentful theory—Curry’s sentences express propositions with truth values—setting out the truths about what is provable from what in underlying formal systems whose interpretation, or rather interpretations, are not taken to be mathematically important. This standpoint, however, threatens to collapse into structuralism, into viewing mathematical utterances as schemata implicitly generalising over a range of (in general) abstra