Weapons of Force are situational, but can be very valuable. Their effect is useless against stationary targets such as turrets and Sentinels, and it’s often downright detrimental versus magical opponents who prefer to keep their distance. They do have several extremely useful instances, though…
Force weapons can be used to maintain distance between melee opponents, and make it impossible for them to land a blow on you if the runic effect regularly fires. It can also be used as a last-ditch effort to put some distance between you and an enemy that is relentlessly pursuing you.
As with most runics, both the chance of the runic firing and the effect (the distance the target is thrown) increase with the enchantment level.