This is not about something being impossible, but something that solves no problem except keeping launchers busy.

The only reason I can imagine for space-based data storage is being out of reach of most police investigators. Recently, a very corrupt banker in Brazil was arrested and his phones were confiscated and, up to now, two have been cracked, with a big effect on the approaching election. If the thing is in orbit, it's a lot harder to confiscate it.