What possible use could that be?
Well, among other things, Customize2 stopped working, because the website that supports it expired. So it can't download a file it needs that tells it where everything goes.
So, I made a list of every file in every backup. Three were made before I upgraded to 2.1, when Customize was still working for me. The other was made after, when it wasn't.
Compare the lists, to find every file that does exist in the pre-2.1 backups, but doesn't exist in the newest. Lots of PNGs, some random plists... and one that seems relevant:
SCP that over. Run customize. Everything works perfectly.
Now, I'd be a little concerned, if I had a really complicated theme to apply, that some of the files weren't where they used to be in 2.0. But, my theme is small and simple, and everything it uses is still in the same place.
So, yay, my phone is my phone again!