If I recall correctly, this was shot at 20 yards from a bench.
Lucky? Maybe. Does it represent accuracy of the pistol at 20 yards? Maybe not - maybe after shooting another 5 rounds that group spreads another inch or two, but maybe if it is put in a machine rest it might do 2.5" groups at 25 yards. I don't know, I haven't analyzed it enough to know for sure.
Knowing the mechanical accuracy is important insofar as giving the shooter valuable data on the best case scenario with that combo of firearm and that ammo, be it a pistol or a rifle.
Comparing that with a rested group shot by hand gives immediate info back to the shooter how their trigger control is. Comparing the info gained from shooting off a machine rest and off a hand-driven rested position with those shot offhand will give more info still...