When it comes to criminal cases, society doesn't benefit from the government trying to win at any cost. Our justice system isn't supposed to railroad the defendant, but to prove his or her innocence beyond a reasonable doubt. It's intentionally set up with the prosecution going head to head, arguing different outcomes from the same set of facts.
Imagine that you have been accused of a serious crime and are now sitting in a police interrogation room. Despite asserting your innocence, police continue to berate you with questions. Exhaustion starts to set in and all you want to do is go home. The question then arises: should you confess to the crime and simply prove your innocence later or do you continue with the interrogation?