Discount Buy allows you to stack your desired coins at lower than the current prices. Let's take BTC as an example:
Scenario 1 - Buy BTC at Purchase Price
If the Settlement Price is smaller than the Knockout Price, you can potentially purchase your desired token at a discount.
Scenario 2 - Receive your Principal + APR in USDT
If the Settlement price is greater or equal to the Knockout Price, you will receive your Principal + APR (in USDT).