I think this lens is not about the ultimate resolution, but the great point is the flexibility of fast change magnification to capture nature in action, with a plus of easier focus (comparing with alternatives at same magnification) and very good contrast, some recent shoots:
A APO microscope objective could give you better resolution focus stacked, but would it allow to froze the action ? Could you stop it if necessary ? Could you change magnification fast and without a IQ penalty ?
A good thing in the cold end of autumn are the solitary wasps paralysed by the cold, much friendlier for photos and not organised in dangerous groups. This one was on the wall of my home and I invited for some photos. The background are mature lemons.