If there was some kind of rail transportation system in the game, having a designated landing zone would make a lot more sense. Then it serves the purpose of being a station that directly connects your landers to the rest of the colony, automatically unloading any resources without the need for drones and letting them be hauled to where they're needed immediately. While passengers can quickly and safely be moved to anywhere in the colony from any landing pad. No need to land them next to their dome, they'll ride the train to it from the landing pad.
The other reason I can see to have a designated landing site is if there's a fuel pumping station building that would automatically move available fuel into the rocket after it lands. This would let you streamline the process of refueling the rocket, since drones could effectively fill the rocket before it lands. Actually, a spaceport could function well as a building that handles loading and unloading of rockets without the use of drones.
Say a space port is a central building that is then linked to separate landing pads, with the option of linking up to six pads around it. The spaceport includes a large warehouse, fuel tank, and customs house, along with rail trams and underground hoses that link up with any rockets that land on its pads to automatically move any supplies and passengers off into the spaceport, while also moving fuel into the rocket. Drones regularly move fuel to the spaceport if the tank isn't full and move supplies out of the warehouse into stockpiles. Passengers will generally move to the nearest dome immediately, but can wait in the customs house if they can't reach a dome, assuming it has access to oxygen and water. If a rail transport system is added to the game, the spaceport would also count as a station for that.
