While I agree that a conviction is much better than nothing, I don't share your faith in the accuracy of our criminal justice system, especially if a plea bargain (aka blackmail) was involved at any stage of the process, whether for the convicted, or for any of the witnesses. Additionally, prosecutorial discretion is a pox on the fairness of justice - but we have so many laws on the books that removing prosecutorial discretion is entirely unreasonable. And then there's the questionable quality of judges exacerbated by the fact that many are explicitly elected (i.e. picked for politics not competence), or political appointees without an appointment process that itself has any reasonable checks, and finally that they are large unaccountable; judicial misconduct appears to be worryingly common, whistleblowers are often at the mercy of judges or their pals, and the process to evaluate claims of misconduct is much too cosy and insufficiently guards against influence by the perpetrator and their friends, and punishments are laughable lax compared to the consequences such misconduct might have for victims thereof.

Of course, at least judges are human and many will therefore be honest and try to do their best despite the system they work in, but it's still a pretty flimsy basis for trust.