It starts out as a variance type given by a city to artists to reside in a building
normally not zoned residential. Not all artists need mammoth macho abstract-expressionist-type workspaces, but many do need more physical floor space than the average apartment, and don’t want to pay for fancy carpeting anyway. An older, perhaps rougher building will give more square footage for the buck. In savvy cities such buildings are made legal for artists to live in because the cities understand that artists draw tourism.
However, give any city with AIR (Artist-in-Residence) variances about twelve years, and all of these spaces will be entirely filled with stockbrokers whose wives have painted one painting in case the inspector comes. The inspector never does come. So the stockbrokers are happy, the building owners are happy, the city is happy (because the tax base on these cruddy buildings skyrockets); no one is sad except the artists, who move to Brooklyn, Omaha, Berlin, and Marfa, Texas, where it all begins again.