The point is obviously as an exercise to pick apart a piece of older technology, figure out how it was built and interacts with the original assets, and create a machine that works for doing that.
If you've got a passion for software and the game in question, it's a rewarding activity in its own right, in addition to being an excellent avenue for learning new languages and tools.
Not every instance of human effort needs to push the world forward in a way that's immediately economically rewarding.