It does seem stupid and meaningless and the breathless pronouncements around it are silly. As you say, they went from house prices to rents to controlled rents. I would love to see a CPI consisting solely of food, energy, transportation and taxes.
That said, I guess what it continues to mean for me is to stay away until the panic move in each direction happens tomorrow morning because I will get my fingers burned no matter what I do or do not do, probably in each direction. So in that regard, I guess it has meaning. 🙂