leaves are basically the plants solar panels, if they're not in direct light they're not efficient but if they do get some exposure they benefit the plant. cutting off leaves isnt beneficial in most situations unless they're infected by mites, or they arent serving their purpose and getting light. removing branches towards the lower nodes redirects the energy the plant was gonna use on them, so less bud spots means less popcorn nugs and more main colas. i train for this reason, trimmin popcorn nugs just isnt worth the time. the highest point always gets more energy and nutrients, keep that in mind when training.