What is the difference between a diode rectifier and an op amp rectifier?
A diode rectifier can turn on very quickly (the silicon diode only needs about 0.026 volts, for the current to increase 2.7X, or about 0.06 volts for a 10X increase) and that rapid current transient causes interference in audio systems and precision measurement systems and in certain radios.

Thus some diode rectifiers, in power supplies crafted for low Magnetic Interference, have series inductors to slow down the current risetimes.

The opamp rectifier does not have this interference property.