Someone who is accused of drunk driving is placed in a very difficult decision. On the one hand, if they are found guilty or if they reach a plea agreement, they are going to be dealing with some very serious consequences. But on the other hand, they should have the chance to make up for their mistake in the months and years that follow, right? It wouldn't make sense to just punish a DUI offender and then never give him or her a chance to rehabilitate their image and contribute to society.
And yet, far too often, the point made in that "other hand" is forgotten. DUI offenders live with the shame of a drunk driving offense for the rest of their life, and the costs associated with it seem to never leave them. Jobs ask about their criminal history; their insurance rates never drop, or only go down ever so slightly; and, in general, a stigma is attached to them that they simply can't shake.
It is in these aspects of a DUI offense that an expungement can be incredibly helpful. An expungement can free a person who has been charged with a DUI by concealing their conviction and making it as if the crime never happened.
Of course, it did happen, and if you were to commit another offense after your charge is expunged, the court would "unseal" your expunged charge to prove you had previously committed an offense. Still, an expungement, when successful, is an important legal tool that DUI offenders need to utilize.