Don't use it much but now I had the perfect task for it, raider on top of an 3 floor building, hitting the structure on top or the roof would kill quest target.
Sneak until quest marker said 30 meter, use fatman, aim high and shoot, bomb go off far to low and target unhurt and all the raiders alerted.
Mirv is even more hopeless in range but that is understandable as its bomblets.
Still fatman would be much better if it had more range, less than 30 meter is too short.