The main difference between fixed and floating rates is predictability versus potential value:

With floating rates, each transaction’s exchange rate may vary due to market fluctuations and conditions, potentially resulting in receiving more or less than expected.

For fixed rates, the exchange service maintains a small reserve to protect against rate fluctuations. This reserve is factored into the rate displayed at the beginning of the exchange, with no additional fees. While the fixed rate may differ from the floating rate due to the risk protection provided, it gives customers confidence in the exact amount they will receive.