When you send Bitcoin you can add an asset along at virtually no cost.
I just sent 8 mBTC and added some GOLDTICKET to op_return. View on Blocktrail. The transaction was a humble 264 bytes. Scroll to bottom of page to see Counterparty info.
Actually, this is not something advanced at all. Every Counterparty transfer adds some Bitcoin dust. You simply choose a larger BTC amount.
Vending machines and exchanges can add a coupon to their Bitcoin payouts. Since there’s literally no cost to doing this, and coupons are common in the physical world, I don’t see why it shouldn’t catch on also in crypto.