I see this everyday in the Bay Area. In this case it seems to be a tech worker. Usually these are bought by some investors in China and the houses are never occupied.
I doubt that's the "usual" case -- yes, cash-only transactions occur, and foreign investment buyers are in the market, but I don't see a ton of vacant homes. I recall hearing from a real estate agent that foreign purchases were fewer than 10% of the transactions, but I have no idea what her source was.
Vancouver circa 2016, though...