Never get anything but bronze when loss of match, I see gold and platinum when winning vs same tier or higher and silver for winning vs lower tier- Not saying this is how it works, just what I have seen happen.
Here's a good thing in a loss.
If you have level 10 Apparel in SE (Swing Edge), they guarantee there will be 1 SE item, even in a loss! So if you lose, and have all level 10 SE, since you cannot increase your apparel, you GET PAID 200 COINS PER POINT. Losses are either 1 or 2 points so for a 500 coin loss, you can get reimbursed 200 or 400 coins.
Yes, I lose alot BUT got my SE level 10 apparel to CMA!