1. You want to be somewhere you can get multiple high-speed fibre hook ups, and reliable power. 2. Office buildings often have some lower-quality space (e.g. a

1. You want to be somewhere you can get multiple high-speed fibre hook ups, and reliable power. 2. Office buildings often have some lower-quality space (e.g. areas with no windows) so you don't have to use super-premium office space. 3. Server racks are extremely dense, so they can make a lot of revenue per square foot compared to a lot of land uses. Good luck running a yoga studio that makes more revenue per square foot. Of course there are disadvantages to city data centres - limited room to expand, and nobody's going to offer you subsidy for "creating jobs".