Moving abroad you're still a U.S. citizens, I'm talking about non-us nationals buying up property strictly to hold/sell later, or to use as AIRBNB, etc... A little old but here's an example: https://www.cnbc.com/2017/07/18/foreigners-snap-up-record-nu...

I get if you are a U.S. national and live abroad some times and come back sometimes keeping a home, but a business man in china just holding 5-10 homes, or using U.S. real estate to launder money, definitely serves no purpose.