The purpose is to save money because they can't afford to divert cash to build new prisons.
They've found a couple of studies (interviews with 5 individual subjects) they claim support "restorative justice" instead.
This means no prison for most crimes (including if you sack off your community service for the crime). It means shoplifting, mugging, most violent and sexual offences will not result in prison so the only thing stopping the criminal is the social penalty they can expect or their own moral compass.
Punch a nurse, spit on a bus driver, steal a school kid's iPhone at knifepoint all on the same day. No prison.
I know you're probably thinking this is an exaggeration of the policy and I can understand why because it seems too absurd and mad. But it's happening later this year.
(Peter Murrell got 5 years 3 months so they probably think they've dodged that embarrassing parallel but some of their sex offenders got less than that - Jordan Linden etc).