Even some small and medium businesses have multiple locations. Local or regional banking, insurance, or real estate businesses for example often have a central location accompanied by a number of branch offices.
Depending on network connection between the remote sites and the central data center, and the volume and type of data being carried over it, accessing data and applications can be quite slow for the branch locations. It is frustrating to employees and hinders productivity.
Microsoft developed BranchCache to solve that problem. BranchCache improves network efficiency and response time by maintaining a local cache of files and information as it is accessed. Subsequent requests for the information can be retrieved from the local cache rather than being re-transmitted each time from the central office.
Windows Server 2008 R2
There are more features that can be found in Windows 7 Ultimate, but not in Window 7 Professional that small and medium businesses may find valuable, but there is a caveat to these features. Even if the version of Windows 7 that you use is capable of Bitlocker, DirectAccess, or BranchCache, you can't take advantage of these features without Windows Server 2008 R2 on the server backend.
Not every business needs these features, and even those that do don't necessarily need them on all systems. Windows 7 Professional may be just fine for desktop systems located at the central office, but laptop systems that roam about, and desktop or laptop systems at remote and branch locations need Windows 7 Ultimate to be able to take advantage of these features.