The big advantage of Office 365 for Education is the low cost. To have all the services that Office 365 can offer, running and maintaining on-premise systems is far more expensive. Office 365 can offer students free Exchange Email and free SharePoint Online, which includes Office Web Apps. There will be a per user per month charge for staff for some functionality.
One great advantage, that again can save money, is that price plans can be mixed and matched to meet the needs of the workforce. So for example some members of staff may not need the SharePoint functionality, so they could be assigned a lower price plan, which could be free depending on services required. (UK Price plans still to be confirmed for Office 365 for Education).
Office 365 can also offer students Lync Online, again for free. This enables easy collaboration on assignments and instant team meetings as well as instant messaging, voice and even video chat with the click of a button. You can also see who is online, just like many other IM providers.
All of these features can be combined with the Office Desktop software for a small charge (per user per month) for both students and staff who wish to combine the services to give a more complete package.