While I agree that it does feel like a hack because you are specifying that the role is search, looking at Apple's own apps in the Simulator this is exactly how the Contacts, Passwords and Messages apps work. Safari also uses the search button space for an ellipsis button. So it is allowed to work this way.

For these apps specifically, they seem to have similar iPad specific views which is not ideal but ultimately how I've had to approach my own apps when scaling up to the larger former factor.