You can be more precise with bolus insulin but for me the most important part about having a pump is the ability to vary my basal according to what I'm doing.
My basal rates vary from 0,4u per hour to 0.6u for hour but when I'm exercising I can reduce it to a trickle. Yesterday afternoon I went for a 10km walk, I used a 50% reduction of basal so very little. Pre pump I would have had difficulty keeping my glucose levels high enough, yesterday afternoon I managed on just 1 dextrose tablet about 20min from the end. Today, it's miserable outside and I've had a sedetary day, I will probably raise my basal slightly overnight to avoid a rise overnight. (I make use of a different 'pattern I've worked out for lazy days)