Leaves feed fruit production, I don't see why you would want to trim off leaves at all - unless it was done for disease reasons. Either to increase airflow or remove foliage too close to the soil to prevent disease, or after disease infects the plant to remove the infected portions.

If you're talking about a true sucker, a new plant coming up from the roots, that I would probably trim as it isn't going to produce fruit for you and it will only eat up resources in the soil, but on the main plant, not really such a thing as a useless branch IMO.