Sometimes the people that use your network make mistakes... heck, sometimes you make a mistake and wish you could get a file back. SBS helps you with this as it maintains previous versions of files on file shares out of the box.
What I think the coolest part is, users can do this themselves! That's right. No more asking "can you recover this file? I just deleted it".
Of course, this responsibility has it's draw backs. But here is the worst that can happen. A user accidentally overwrites a file with an older version, only the things changed on this file since the last update are lost. Not the entire file.
I think this is turn for the best, it means less administrative work for you, and more power for your users to do their job.