On rehearing, the appeal court will focus on whether it can be satisfied of guilt beyond reasonable doubt. This differs from a verdict insofar as if the court is not so satisfied it will usually order a new trial, rather than enter an acquittal, although the latter course may be taken in appropriate circumstances, such as long passage of time, the completion of a sentence, the unavailability of witnesses, or the compelling nature of fresh evidence of innocence.
No one is saying that the review-or-rehearing classification is watertight for all kinds of appeal. Appeals brought under s 232(2)(c), claiming a miscarriage of justice for any reason, might involve issues concerning the correctness of a trial judge's exercise of a discretion together with other issues that are appropriately considered by way of rehearing.
[Update: For application of Sena, (to a case decided before the judgment in Sena was delivered), illustrating a failure to give adequate reasons for convictions in a judge-alone trial, see Webster v Police  NZHC 1335.]