i break mine up too. not as much for a bowl as i would for a roll. just little pieces, for all the reasons listed above. also, i find that if you break it up, the last few hits taste better. you know how a bowl tastes when it's beat or almost beat? well if you don't break it up, you gotta suck harder to light the last little bit and get more of that shitty, cashed taste. do i even make sense?
I advise to those who break up buds for pieces to put a little baby nug at the bottom to stop all the finely broken up bud from falling through.