Git is the latest and coolest software, and SVN is the outdated old one. When you tell SVN that you want to create a new branch of your code to have some fun, it creates a heavy weight dumb carbon copy for you. But Git is intelligent, it won't create a new copy for you instead it will only keep track of the things you're adding/removing/changing with respect to the original sources.
I hope I made the point, for more let's have a telephone call some time :)