When a 62-year-old financial advisor bought a two-bedroom Manhattan co-op recently, he showed up at the closing with a check for the full $970,000 purchase price. No mortgage? “The money I had in cash was sitting getting 0% interest,’’ explains the man, who asked not to be named. “It made absolutely no sense to borrow.”There were other benefits as well to buying for cash, he says. He figures he got a “liquidity discount” for being able to close quickly—the asking price had been $1.05 million. And he avoided the hassles and paperwork that come with getting a mortgage these days. At the closing, he gloats, “they spent more time making photocopies than anything, so we sat discussing Broadway plays.”