The big difference AFAIK is that in USA, most of the cases end up with a deal between parties. In Japan the notion of deal doesn't exist.
Anyway I don't know how much you are helping the USA here in your argument. A deal in the US is often like:
"Look, kid. With this deal, you get 1 year in prison. If we choose to prosecute, you are looking at 30 years to life. Your call. Remember, you have a [kid|mother|girlfriend]."
Who would risk going up in court, even if you maybe didn't even do very much? It's basic economics. The risk is too great that jury is going to hate you, no matter what you did or didn't do. Better take the bargain and cut your losses.
Settlements, for civil cases, not so much, and I think it's an overall positive.