>For still images you get exactly the same result.
No, when setting the crop in camera, the meter will consider only the cropped portion. That is true for any crop mode. In most cases it will not make a meaningful difference, but if you happen to have some bright light just outside the crop area but within the 35mm frame, the in camera crop will give a better exposure.
That said, I rarely use in camera crop since the flexibility of having the entire frame is more valuable to me than avoiding occasional exposure errors.