I don't know what kind of autism that compels the dev to create a complex damage system with limb damages only for the combat to be a simple click and watch (or kite) your little men murder other little men.
Dwarf Fortress laughs at you puny mortal.
Isn't that game turn-based? And you don't even get to choose the body parts you're aiming?
Nope it is RTwP.
As with everything in this game, limp damage is more of a strategic/economic decision: the decision is not what to aim for, but whether to run the risk of your own harpoon shooters to friendly fire their comrade in order to defend the town (harpoon damage has a very high chance to take a limb in a single hit), or whether to avoid firing into melee but run the risk of not repelling the enemy raid at all.
Or whether to prioritize manufacturing replacement limbs (which requires precious research artifacts to be researched, unless you are happy using the crappu ones), or mineral automation, or turret power.
Also the armors with the best limb protection usually don't protect the torso as well as the best breastplates, so you are trading a lower chance to lose a limb (or get unable to swing your weapon effectively); for a higher chance to be out of the fight or dead.