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?
spoiler
You do remember correctly. Bashar Miles Teg at one point utilizes a variant of that technique. They mount pairs of shields and lasguns on anti-g platforms and use them as surprise tactical nukes in a battle against the Honored Matres. That is one of the many epic af moments in the Dune saga. I think I will have to read it for the umpteenth time now :)