Outcomes, evidence, proof - you choose.
Stride gum has their campaign, “The ridiculously long lasting gum.” I don’t know if they have actual proof, but it equates the value of sustainability to the customer.
It is the same with medical devices. If I can prove use of my device will prevent a potential resource depleting morbidity, I can justify the use of the materials used.
Justify the benefits so a 4-year-old can understand and it is a simple sale.