What is the importance of the yo-yo?

It keeps you........busy? Well consider it a defence mechanism, if some guy/girl tries to mug you you wip it out and start to swing it like a flal, or if someone robs you and tries to get away your wip it out and throw it so it tangles at there ankles so they trip and fall with a *BOOM*, make sure not to injure them or they'll press charges. But its great for protection, and fun :D Why Have A Yo-Yo Yo-yos are one of the worlds greatest inventions For multiple uses see above