For a time, tall, blocky, stone tower-houses were the rage in Ireland. Perhaps 2K survive today, and thousands more are rubble or gone. Since they took considerable labor, they must have been valued.
I read an article about them today, describing murder-holes and machicolations, which are design details that were all about defense. The author also described a battering-ram test his squad(?) did, which took minutes to take down the door. His conclusion was that tower-houses looked far more defensive than they actually were.
I think they were about elevation—about keeping a lookout. And perhaps visual communication (flags? smoke?) among the many towers, as they were often built close enough to see one from another.