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 remember that the location of the reaction is random and happens anywhere along the beam path. So they are safer to use at long range like from orbit as the reaction is less likely to be close to the shooter.