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?
Given the basic premise from the very beginning, where the emperor wants to destroy house atreides, I doubt it. If the houses were going to honor their promises, they already should have