Japanese anti-aircraft rockets versus British UP launchers

Were Japanese shipboard rocket launchers as ineffective as British unrotated projectiles?

Japanese launchers had the more useful concept: explosive rockets could blanket an area with timed bursts, while British UP weapons attempted to create an aerial minefield.

British unrotated-projectile launchers were intended to create an aerial minefield. Japanese launchers instead sent explosive rockets downrange to detonate on contact or after a timed delay. Cheap rockets could place a barrage over an area where conventional Japanese anti-aircraft firepower was limited. A proposed alternative for the British launchers was to fire proximity-fuzed rockets, although that is a hypothetical improvement to the original system.