Bloomberg wants more of them in NYC. Yglesias defends the idea:
Laws regulating the smallest permissable size of a dwelling—something like the rule against apartments smaller than 400 square feet in New York, or the very common rules in the suburbs mandating a minimum sized lot for a single-family home—are among the most straightword tools in the exclusionary zoning toolkit. The basic issue is that income-constrained individuals naturally make trade-offs among different virtues. You might get a larger dwelling with a longer commute. Or you might opt for a smaller dwelling with better local amenities. A rule against small homes prevents people with relatively modest incomes from making the trade-offs that would allow them to live in areas that the commute or the amenities makes desirable.
Howard Husock concurs.