Unless I am mistaken, the court has a tighter rein on the discovery process in a criminal case.
A criminal defendant would have broader latitude to unearth evidence than a civil defendant. A defendant in a criminal case faces time in prison, loss of liberty, etc., or (depending on the case/state) death penalty, so the courts are far more lenient with them. Prosecutors have more limitations. Defendants are entitled to anything, all proof/evidence, that would help their case. Tell me PP would want that!!!