As far as I can tell, there you can only borrow other cryptocurrencies against bitcoin, not bitcoin vs. bitcoin. Therefore you also have an LTV and the lender has a default risk. Furthermore, you are dealing with other shitcoin chains.

What I describe above is pure bitcoin on-chain (and potentially lightning at a later stage). Bitcoin vs. bitcoin with the goal of deferring any capital gains tax to keep optimal compounding. There is no default risk, the interest rates would be likely much lower and everything is just relying on the security of the bitcoin blockchain and nothing else.