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?
Miles Tek does that in the later books, IIRC. strap a lasgun to a shield generator, instant pseudo nuclear bomb.
Edit: I guess the difference is that they are dropping the whole package, not just the lasgun.
I have a much better question, why not build a spice harvester that has a carryall attach to the top of it permanently?