True but what about being able to place spike pits or fences outside the structure to give more defense. The system I am thinking of you would be able to place structures outside the walls of the building too. All in an easy way rather than having to walk over to a spot to place it (given u have the right materials within reach of starting point).
The same as cars need power, gas, solar and water to function, you would need to manage these once the structure is built. If your generator is damaged then all the lights and turrets go out. And maybe someday down the track when hordes of zombies storm your fort you would have to repair and upgrade your base to survive
or have a good escape tunnel (z-levels!).