Is it feck. What about the management of the construction process? Just because the building has been designed by AI doesn't mean you don't need an Architect to implement changes, or a contract administrator, construction managers, quantity surveyors, construction lawyers, quality control, health and safety, labourers, multitude of various tradesmen (plumbers, joiners, electricians, roofers, etc) none of those can realistically be done by a machine. Sure you can maybe get a bricklaying machine or one of those plastering machines, but you still need people to load them, move them about, tell them where to lay bricks or plaster. Then you need to move them about, spend time setting them up, commissioning them, decommissioning them, taking them apart, putting them away.
There's no way any fully automated machine building can be done with any kind of cost benefit. It will be cheaper, easier and much more easy to manage with a fully human workforce. You'd be surprised how many things change from a day to day basis on a construction site, that all needs logging, costing, and arguing about whose fault it is.