New Google sync options - still no real information?

[lenasverige]

During Google I/O new Google sync options were presented. Sync App Data in particular. But since then no real information and explanation on how this works has been available (this is so "Google"). This article: Google 'App Data' sync setting appearing on devices | Android Central also doesn't really explain anything.

So what is this Sync App Data is for? Syncing app data between devices? Has anyone managed to restore data with it after a hard reset for example? It doesn't seem to sync for me automatically btw, even though I have the box checked..