I've been playing Deathsmiles for some time now, and I still can't seem to figure out the usefulness of the lock-on shot. I find it slow and difficult to use effectively and never use it, yet I see pro replays using it all the time.
When is it best to use the lock-on shot? Are any bosses more susceptible to it than others? Do any enemies drop more items as a result of being killed by it?
Basically, why should I ever use the lock-on shot?