Oil does several things in aircraft engines (cooling, lubrication etc) but if you have a TCM turbocharged engine, oil also assures that the wastegate operates properly.
For this to happen, the oil must be hot.
Watched in amazement some years ago as the president of Pacific Airmotive in KBUR taxied out for takeoff in a Cessna 402, did not bother with a runup( his usual forte)...and on takeoff, shoved the throttles full forward (recommended by the POH) only to find that three cylinders on the left engine, and two cylinders on the right engine separated from the case, leaving bits of metal all over the runway.
Hot oil was very necessary to ensure that the turbo wastegate operated properly, limiting the MP to the proper number.