Governments are preventing companies from rapidly dropping house prices. But because they’re not worth what they’re forced to keep charging by the government (government isn’t forcing anyone to buy for example), developers are needing to add extra value to the sale to get buyers, hence the gold bars.

House is worth $300k, but the government is forcing you to list it for $500k, so if I throw in $200k worth of gold bars, the whole sale is worth the price.