I am but a simple person. Someone please explain why we need a law to exonerate innocent people?

Prime Minister Rishi Sunak says the government will bring in a new law to "swiftly exonerate and compensate victims" of the Post Office scandal Under the plans, victims will be able to sign a form to say they are innocent in order to have their convictions overturned and claim compensation

As you get older, everyone seems to get young. I can't imaging having so much responsibility at 34!