Three Millennium Tower condos sell for $9 million apiece

Often foreign buyers have no plans to live in the US, they're buying housing as an investment. In the case of many Chinese, they want to keep some money overseas (this is particularly true on the west coast). In Boston you have the phenomenon where parents are buying condos for their college-aged kids to live in, but that doesn't mean the family will use the condo after the kids graduate.

It doesn't really meaningfully contribute to the city's diversity if someone from overseas buys housing here that they then leave empty or rent out. It does contribute to housing price increases.