We will list other uses for Han's missiles below. However, the missiles are BEST used as part of your mix-up in the motion change. You have four shots per round. You should use ALL of them from the motion change. Han's missiles are slow to fire.
Missiles work better in larger arenas because they can track without hitting a wall.
If your opponent is hit by a guided missile after you've fully recovered, you can try and pull off an air combo. Block low because the low pops out more quickly. In large arenas you'll be hurt if you don't jump or projectile-evade the missile. If you like kicks and LOTS of them, go for it. If you want to use kicks and LOTS of them, go for it.