In the Dune universe, when a laser weapons hits a shield, both are destroyed in a nuclear explosion reaction.
So instead of building nuclear weapons, wouldn’t it be easier to tie a timer and a “parachute” to a laser gun and drop it from orbit onto your enemy’s city?
I actually just came across the line that explained this in the first book. apparently, after the fact, there’s no way to tell the difference between this and the use of an atomic, so using this strategy could get your family accused of illegally using atomics against another house.