Completely pointless, but I always wondered . . .
In all of the TOS movies, why did they only use ship-based phasers in The Wrath of Khan? Depending on the movie, they may have given a reason why they didn't use the phasers (like in TMP, the bit about phasers being tied to the warp core in the wormhole scene), but they wouldn't have had to do that if they just used them instead. Maybe torpedoes were easier SFX?