Check the numbers below to see what can go wrong
Even if everything functions correctly, it still takes considerable skill by the aircrew to deliver these weapons, often in difficult and dangerous circumstances.
The missiles cannot differentiate between a tank carrying soldiers and a tractor carrying civilians. The military personnel have to make that distinction.
All weapons have parameters - "release conditions" - outside which they are unlikely to hit the intended target.
A laser-guided bomb  has to be released at a height, speed and angle that give it a reasonable chance of latching onto the guidance cone of light.
If smart weapons "break lock"  losing their fix on the target, they become uncontrollable.
It takes some time from a weapon being released to arrive at the target. If the target is a railway bridge and a train carrying civilians arrives while the missile is in flight, there is nothing the crew can do.