I hope this is not taken seriously. In the AW139 you should trim into a turn.
Why, specifically? Is this really how the aircraft is flown in practice, or a 'simulatorism' to assist accuracy in training? As an example, we used to get pilots back from FSI with their new S92 ratings who tried to lift into the hover using the collective beep trim and their feet on the floor!
Apart from any discussion about the ability to release the controls and return to wings level trimmed flight (sounds like a reasonable concept to me), there is the practical reality that pilots tend to spend too much time looking in at the ADI to check the angle of bank and then 'tweeking' the beep trim back to wings level.