Hello. I see different platform like nexo, blockifi, etc... that can borrow you crypto or stablecoin. I'm here to ask if you have a strategy for example you borrow btc with an interest rate of 6% and then you use it on defi with 8% APR. Thanks for helpful. 
I don't know about crypto or stabelcoin lending yet, but as MK4 says it makes sense, if the platform says they give x% APR to certain assets, which means the amount could change. This is another case due to the strong price movements of Ethereum and BTC, which have dropped other coins.