Citrea has launched its mainnet, introducing a Bitcoin-native ZK-rollup that includes BTC-collateral lending, BTC-structured products, and the ctUSD stablecoin. Backed by Founders Fund and Galaxy Ventures, the project aims to convert idle Bitcoin into core DeFi liquidity, with ctUSD serving as a dollar-backed stablecoin issued directly on the rollup. This approach seeks to minimize cross-chain risks and liquidity fragmentation. The launch has sparked debate over Bitcoin's block space usage, with proponents arguing for its use in non-payment financial applications to sustain miner revenue. Critics caution against potential risks from complex DeFi structures. Citrea's testnet showed significant early demand, with data availability usage reaching notable levels. The project targets $50 million in DeFi liquidity, positioning ctUSD as a compliant, on-chain liquidity anchor.