I assume this kind of a licence has the same things to makes it different from a documented person, like able to get into a federal building and ride a plane
If there is someone willing to pay money for a service, there has to be someone wanting to do it.
statistics on California, showed a reduced number of hits and run
In Maryland the license is for driving only. It will not get a person on a plane or any place where secure ID is required. Being a citizen is not a requirement for insurance - having a legal license is. A new driver applies to an insurance company just like a new driver who is a citizen does. The company uses the same tables - age, gender, credit scan, how much driving will the new driver do in a year - does he use the vehicle to commute long distances, etc. Age of vehicle and type factor in too. If the new driver cannot get insurance from a commercial carrier then he can buy insurance from the state. There is no subsidy at all for this, the rates are high, and any claims the state insurance company pays out, the policy holder is liable for paying back.
If the undocumented driver is stopped, some sheriffs in Maryland will do an immigration status report and may take the driver in for possible deportation. Having the legal right to drive does not change that. What it does do is make it possible for the alien to have insurance so he meets the same financial responsibility standards as any citizen driver.