My limited understanding is that entering a plea is not related to emes or sheker. It is a strategic move, no more, no less. The court is not a place where emes or sheker matter much, procedural rules are far more pertinent. The things one says in court are not meant to represent truth, and therefore its like playing poker – would one need to represent the truth there?
Would someone actually advise a person to say the truth and run a strong risk of being put behind bars for ten years instead of copping a plea and paying 10K?