The point is that in the middle of a battle involving ranged and non-ranged units, a freshly killed unit is still being bombarded with missiles. There's a lot of unnecessary friendly casualties due to this behaviour.
Outside of big skirmishes, units tend to venture further out than is desirable, which is a nuisance.
So, the reasons are solely gameplay.
I hadn't even thought of the ethical considerations.
Separating patches is a good idea, I'm just lazy when it comes to creating new branches.