At 12nm and looking at MSAs, the figure quoted on (Jepp) charts will be the MSA out to 25nm. Therefore, if you are under positive radar control, you would be safe down to 2000 ft. This, of course, does not absolve the aircraft commander of his responsibilities towards the safe conduct of the flight.
The benefits for ATC and the operator of doing this are that it enables an intermediate app speed (210 kts ish) to be maintained for a longer period and results in more movements/hr for atc and less fuel burn for the operator.
If in any doubt though, wait for the G/S.