Zest Protocol has launched BTCz, a $BTC equivalent that allows holders to earn yield through the Babylon staking system on Stacks. The $BTC yield comes from Babylon staking or other $BTC staking protocols. Zest users deposit $BTC to receive BTCz, which appreciates in value over time. The security of BTCz is enhanced by Stacks' ability to read Bitcoin state, eliminating the need for third-party verification.