What is a refund without return?
Not every refund is a return. With a refund without return, the customer keeps the product but gets (part of) their money back. You lose the revenue and the product.
Why it matters
Refunds often sit only with your payment provider or in your customer service, not with the order. That is why they are missing from the profit calculation of products and campaigns. In the Commerce Intelligence Model they count as leakage, just like returns and commission.