Towers improve the range of vision (at least in terms of distance of the horizon) . In mythology vision is often used as a proxy for wisdom -- the eye sees thin

Towers improve the range of vision (at least in terms of distance of the horizon) . In mythology vision is often used as a proxy for wisdom -- the eye sees things, it points out things, and then wise thoughts (&actions) come forth to enact the will of the viewer (the wizard) . As the stackexchange answer says it's a trope, but I think it's much richer than that. The territory covered by the field of vision represents the depth of wisdom and domain of the wizard. They are in a sense able to "rule" (or influence) over the area through a perspective and foresight that others do not have on the ground.