Very likely not much except to get a freebie, token interview which you might otherwise not have been offered. If you would anyway have been offered an interview on the merits of your application, it might help in securing an acceptance. Truth to tell, the differences among among many applicants are relatively insignificant. Yale once did a followup study on what happened to applicants they interviewed but who didn't make the final cut. All of them found places elsewhere. Yale concluded from the study that if they had accepted the ones they rejected and rejected the ones they accepted, it would have made no difference to the outcome.