Configuration management is pretty essential for any big project, and even for medium and small sized projects. Having configuration management set up for a project opens up an easy and efficient avenue for a team to build and maintain complex programs or applications. It allows multiple people or teams to have access to different parts, and limits access to the same parts, of a project without allowing conflicts in file version and incidents like accidental overwrites. It also allows the team or team member to verify the changes they commit to a project, so accidental catastrophic losses can easily be avoided.
Personally I have not worked on projects big enough to merit the use of configuration management, with the exception of some experience in an ICS 212 C/C++ class as part of an assignment. The use of configuration management was only a small part of that assignment, included so that my class could have some exposure to systems that we might interact with in the real world. Other than that however, I have never personally run into an issue large enough to merit having implemented configuration management, but I can easily see the advantages of implementing it in other possible projects in the future.
As far as Github, the most popular cloud based software hosting platform, and Git, the most popular technology for configuration management, I am of the opinion that Git is popular because of Github, these days at least. In the days before Github was around, Git would certainly have been adopted readily by those in the know or those who saw the benefits of the system. Especially as it was developed by Linus Torvalds himself originally. But, I believe that many more people recently, would likely be very familiar with Github independent of Git. I had not heard of nor researched Git before this semester, but knew of Github and its uses for a few years, as an example. Having been exposed to Git and Github, I certainly will be making more use of both of them moving forward in both my academic career, and for personal projects. They are solid systems for configuration management and relatively easy to use.