Players need a save file to unlock characters, stages, and other content in the game. Without a save file, players would have to start from scratch every time they play, which can be frustrating and time-consuming. A save file also allows players to track their progress, see which characters they've unlocked, and which stages they've completed.
But Piccolo shook his head. "No, Goku. The file says... it's my turn." Dragon Ball Z Budokai Tenkaichi 3 Wii Save File