Oh, and one more point. Japan has a 99% conviction rate. Would you call that the epitome of rational decision making because defendants know they are going to prison before they set foot in the court room?
It depends. If 99% of the defendants are guilty, sure—it’s a very good thing, because it adds a higher level of predictability to those who are choosing whether or not to take certain courses of action. It better allows people to adequately assess risk and to internalize all the costs of action.
On the other hand, if less than 99% of the people are guilty, then it is bad, because an element of randomness (which you ought to prefer) is injected into the equation.
People are unable to adequately assess risk in plotting their behavior. This is unquestionably bad.