I imagine that the power of the pardon has been abused many times in its existence. What is extraordinary right now is it’s use as a preemptive weapon to shield political allies form any kind of investigation and Grand Jury investigation into criminal matters.
Before Biden leaves office there is no telling the wide and scope of the Pardons he might give and the repercussions of such actions. He opens the door for future Presidents to issue pardon for crimes that have no even happened yet.
Imagine a President giving out Pardons for staff and allies at the very beginning of his term for any and all crimes that will be committed in the next 4 years. That could happen.
You understand my points.