This kind of LEMP weapon could be theoretically deployed as an air defense system to neutralize conventional (IR guided or radar guided) missiles, but could also be used to neutralize UAVs, which are dependent on electronic systems.
In some sense, using nuclear weapons is an admission of military failure: failure of those nifty, surgical, precision-guided, multimillion- dollar bombs and missiles armed with "humane" conventional explosives, failure of military stratagems and traditional battlefield skill.