Harddrive space is consumed like flour or sugar is, not as eggplants are.
Nobody says "I want n pounds of eggplant", rather they say "I want n eggplants". They then pay based on weight, for the convenience of the grocer.
On the other hand, you don't want "n bags of flour" but rather "n pounds of flour". If flour were being sold such that more than a miniscule single-digit percentage of that weight were actually packaging, people would be justifiably upset.
Nobody says "I want n pounds of eggplant", rather they say "I want n eggplants". They then pay based on weight, for the convenience of the grocer.
On the other hand, you don't want "n bags of flour" but rather "n pounds of flour". If flour were being sold such that more than a miniscule single-digit percentage of that weight were actually packaging, people would be justifiably upset.