This allows you to put your local tasks outside your workspace and versionize them with git. This way you can use git to move your local tasks between machines. I really like this as I frequently use different machines and now I can not only share source code betwee them but also my mylyn taslks.
As Steffen told me, simultanous access to the Mylyn tasks might cause task corruption but I don’t think that is an issue for me as Git takes care of conflicts and I do not have two machines writing to the same local file.
Fun times with Git and Mylyn!