[quote=GreivousKhan]
The real challenge is getting a hit with that charged up attack, to use maybe a bad example, imagine if Piccolo had missed with his special beam cannon. The fight would have ended badly for them right there. 

And he did indeed need Goku to hold his brother still for him to power up his special sauce.
[/quote]

No, that's a good example.

[quote=Alphakoka]
And that's how it work. If you block a prepped attack with unprepped defense, then some of the attack would go through. If you evade it then the prepped attack will miss and became wasted charge.
[/quote]

Ok, and if you aimed with a pistol for ten rounds... against an all-enclosed tank with no viewports? Are you going to hit the pilot? No. Prep = shit vs a blatantly superior defensive tactic.