"these lists will never have any real relevance to the real world."
Excuse my English, I will try be understandable.
I do not agree. It is not accurate, but some relevance, it has. When you talk about saline implants you can have the amount of cc registered, even if there is some leakage. This gives you a good idea of the volume and mass of the implant, even if it is not accurate. See, the larger the implant, the greater the number of significant figures in the volume measure, so you will not need such a precise measurement in the ml box if you will already be working with liters.