At least in theory... lower tower construction costs, lower ATC labor costs (especially in high cost-of-living areas), and economies of scale from colocating mu

At least in theory... lower tower construction costs, lower ATC labor costs (especially in high cost-of-living areas), and economies of scale from colocating multiple towers into a single facility (i.g. ability to quickly reallocate controllers between tower sites based on observed traffic, or even having controllers operate two towers simultaneously if traffic is light). This last one is already done for approach control. Some areas have a consolidated TRACON facility, like NorCal Approach. At night they'll merge all the radio sectors together, and you end up talking to the same controller for half the state.