You can actually lend your btc at a pretty good rate. Over 5% on BlockFi. Rates are lower on defi exchanges because there is a risk premium as people figure it out and actually borrow.
As always, where there's a return, there's also a risk.
You could also buy USDC (no fees through coinbase) and BlockFi pays 8.6% apy.
Ally bank just emailed me that they are lowering the APY again. It is lowered almost monthly and is almost 0 now.