The overarching goal of any business is to make a profit, and cutting operational costs wherever possible can greatly impact that goal. The greatest benefit of moving to the cloud is unsurprisingly a financial one. The financial model associated with the cloud is predictable and economical. There are no upfront costs, flat-rate monthly fees per user and/or amount of bandwidth used, Additionally, it is easily scalable in either direction which allows you to control costs.
Furthermore, switching over from legacy servers to cloud servers eliminates the need for continual server environment refreshes, reduces demand for IT support staff, and saves on energy use.