In general, the strength of a structure under compression tends to be limited by buckling failure. This consists of an uncontrolled lateral bending motion; when the force placed on a structural element (such as a pillar) exceeds a certain critical threshold, the amount of energy released by moving the ends of the structure closer together through bending exceeds the amount of energy needed to overcome the stiffness of the structure itself. The resulting strain on the structure creates uncontrolled stress, which then causes the structure to break. Even if the structural element survives the sudden bend, it will no longer be resisting the downward motion of the load, and is thus useless from a structural point of view.
Buckling failure can be prevented by making the structure stiffer. This can be done by adding more materials, or by reducing its aspect ratio (i.e. making it wider in proportion to its height). The latter forms the rationale for flying buttresses found on old (terrestrial) cathedrals. However, both of these solutions increase the cost of the structure. Using a force line to reinforce the structure at regular intervals accomplishes the same thing (prevents uncontrolled bending) but at a much lower cost.
Anti-buckling fields not only reduce the cost of tall buildings, but also allow for unusual architectural styles. Because anti-buckling fields use magic to replace the innate stiffness of the structure, the structure therefore is not restricted in its aspect ratio. The result is that a building can be immensely tall relative to the width of its foundation, and will not sway in spite of this. Additional force lines can be used to cantilever additional structure to either side of the main column, resulting in buildings that are wider at their roof than at their base. Structurally, supporting materials in such a building can be consolidated into a single central pillar that does not obstruct usable space.