Every stadium in the game features a large electronic screen.
In Mission mode, the screen will display an 'M' icon.
In multiplayer matches, the screen will display a skill icon.
If you hit the scoreboard while one of these skills are displayed, you will be able to trigger a 'skill ball' against your opponent. When the screen is triggered, it will be turned off for a while until the next skill pops up.
Thus, hitting the scoreboard before your opponent will give you an advantage over your opponent during gameplay.