Why Should i use sharepoint, already have file server and network share for storing documents!!!

Often it is seen in existing development teams, there is a degree of lethargy to move or learn a newer technology especially if its from Microsoft. Making the agile teams adapt sharepoint is the most challenging task. They exactly know what they are doing, how they do it and why they do it when it comes to document storage. Questions arise, what has sharepoint to offer when it comes to document storage?
My take on this:
If your files are less than 50 MB in size
If you have a team where users are making changes to documents (same or different) and there is no control on tracking changes
How do you track a document that was changed several in last 10 minutes? i am sure you cant see the history of the documents using a file server or network share
check - in check out feature
Sharing document across without having to email thereby reducing network congestions or bottlenecks.
Sharepoint document library provides all the above features. Go for sharepoint implementation within your team.

Note: If your files size exceeds or is in the size of 300 MB, its best to go with file server or network share.