[lozenge]

There are "official" ways to fill cups that reduce the variance a bit but you are right. Humidity, pressure and temperature also affect volume more than weight and can throw off a recipe. Plus, scales are O(1) while cups are closer to O(n) (maybe O(log n) if you have many different sizes of cups... and are willing to clean them all...)

Cue all the Americans(who have much bigger kitchens on average) explaining why scales are unnecessary and cups are the one true way.