Can anyone please explain a little what
STAND-OFF RANGE WEAPON means?
It means
YOU are able to attack a target, usually a ground position, while
YOU are outside of its maximum defensive capability.
A simple example would be two poles of different lengths. The pole with the longer length, hence with the longer reach, would be considered a 'standoff weapon'.
The longer the distance of this standoff weapon, the greater the reliance upon the weapon to be 'smart' to some degree.
The main issue is the mobility of the target. Fixed ground targets are technically easier for a 'smart' standoff weapon to be effective, and technically easier to develop such a weapon. A gravity driven bomb have limited flight time, using the word 'flight' loosely here, and that time is created by the altitude from which it was dropped. Obviously, a bomb dropped from 3,000 meters will have a longer flight time than the bomb dropped from 1,000 meters.
A smart standoff weapon must be able to deal with the altitude variable seamlessly, in other words, it cannot complain to the pilot that it needs X altitude before it can be dropped.
A longer flight time equals to a longer sensor acquisition time for that fixed ground target. But the downside to this is that the higher the delivery altitude, the greater the odds of that fixed ground target to detect the delivery platform, which equals to alerted countermeasures.
All of this must taken into account during mission planning of that assault on that fixed ground target. You must plan on the approach altitude ( cover ) and the release altitude. You must know your weapon from training and know it intimately.
Now...Against mobile targets.
It is feasible to attack a mobile target with a gravity driven smart bomb, even though it has a limited flight time. It depends on the terrain and the target's ability to move on that terrain.
Say the mobile target is a missile launcher.
A missile launcher becomes a fixed target before launch, therefore, the best time to attack and destroy this target is when it is mobile. Now do you see the problem ? The best type of target is the fixed, but for a certain type of target ( missile launcher ), it is best to attack it when it is moving. Is your smart weapon -- smart enough ?
Which direction is it moving ? Now it becomes a math problem. If the missile launcher is on a paved road and the terrain prevents the vehicle from leaving the road, the math is easier because the direction variable is pretty much one-way -- the vehicle's heading. But you cannot count on this to be constant. Given the limited flight time, your smart weapon must be able to compensate for any possible direction this vehicle can take. Again, this falls back on mission planning. If the terrain is tropical with high topographic features such as hills and/or ravines, odds are good that this missile launcher will be restricted to which direction it can move. On the other hand, if you are dealing with desert type terrain, like in Desert Storm, then the missile launcher can travel practically anywhere. Does your smart gravity driven bomb have sensors ? Can it alters its drop direction to compensate for an unplanned maneuver by the mobile target ?
So just because you have smart weapons, it does not make mission planning easier. In fact, the burden of target intelligence is even greater and mission planning takes longer.
Note: This excludes nuclear weapons simply because of the scale of destruction a nuclear weapon can deliver.