La trader, are you suggesting that converting xrp earning 4% over to usdc earning 8% would earn you more?!
Remember you are paid in the currency you are staking. So if xrp goes up in value it all goes up. All interest earned and original amount staked are all priced in real time. So interest earning potential could go up 100 to 1,000% on top of the 4% apr if you hold.
Usdc will always be flat and interest will always be 8%. Not a great option if you believe xrp will go up in value over time.