In addition to the other comment (a lot more engines in the first stage of a full stack than the test hopper), there's also the impact of mishaps - an exploding

In addition to the other comment (a lot more engines in the first stage of a full stack than the test hopper), there's also the impact of mishaps - an exploding fully fueled full stack would have dramatically larger impact than the partially-filled test hop. Then there's he environmental impact of more frequent launches (originally the area was approved for 12 falcon 9 flights a year) - sound impacts on wildlife, habitat impact of larger construction areas, more staff around reduces habitat quality for wildlife, etc.