I'd say erratic shifts in housing prices are an independent "bad" apart from the credit risk (e.g., finance) component. At the most basic level, housing is a requirement for living. Particularly owning a single-family house is both the best financial decision for a family that lives in the same metropolis for more than 15 years or so, and a virtual requirement to be accepted as truly middle class. Housing should be affordable.
IIRC some Yale economist showed that over the long term, housing more or less tracks inflation. If you can save money by renting and invest the difference, you would be far better off.
That said, given people's saving abilities, forcing them to send a cheque for a fixed amount every month is probably a good idea.