Does that really add that much more value over and above essentially the same setup except the tabs are implemented by your browser on different web pages?
It does , because this is one platform with fully inter operable work item, build number, change set id , deployment server integration readily available , if you notice the individual tools, they come from different org's and have different way of working , except that they have a rest API exposed for you to integrate any other tool in a limited way. Its like when a developer makes one line of code change , he or she can use this platform to shepherd the change into production in a fully automated manner and take responsibility for the same.
