Some pack, some sift and scoop. You have to know what the recipe wants. Weigh is in my opinion superior, it just wasn’t widely accessible before cheap digital scales.

In my four decades of baking, I have never seen a recipe that calls for packing flour. It is always sifted, spooned and leveled, or weighed.

Weighing is the only weigh.

Brown sugar should be packed; flour must not be — you’ll get substantially more mass per volume than the recipes assume.

four is alway sifted - to get the mouse droppings out. In our modern world nobody has mouse droppings in flour but tradition is still strong. Weighing doesn't care but if you are scouping as much air as possible is what the recipe assumes.