It isn't but it is a hedge. You put that down payment in some other asset class (stocks?), pay about half of what a mortgage would be currently and then profit when the RE asset bubble pops and buy when it's cheaper. And while your waiting the stocks themselves will probably have a gain of some sort.

The correct stock/equity analogy of renting is that you don't own shares of XYZ; you do volunteer work for XYZ. You pay XYZ regular dividends instead of the other way around, you maintain the equipment of XYZ and so on.

I think what was meant by the short was selling at current prices and holding the money, intending to buy back after a crash.