Citrea Bitcoin ZK Rollup mainnet goes live, reigniting the battle for block space

The Bitcoin ZK-rollup project Citrea, backed by Founders Fund and Galaxy Ventures, has officially launched its mainnet, introducing DeFi lending, structured products, and the native USD stablecoin ctUSD, which uses BTC as collateral, aiming to bring "idle Bitcoin" into a complete DeFi and payment system.

Citrea stated that the active DeFi liquidity at the initial stage of the mainnet launch is expected to reach $50 million. ctUSD is issued by MoonPay, pegged 1:1 to cash and short-term U.S. Treasury bonds, and is not a cross-chain asset but is natively issued on Citrea to reduce bridging risks and avoid liquidity fragmentation. The project has also sparked controversy: as block subsidies decline, should Bitcoin miner fee income be supported through non-payment uses like DeFi and stablecoins? Supporters argue that this is a sustainable source of demand, while opponents emphasize that Bitcoin block space should focus on simple, censorship-resistant payments.

It is noteworthy that during the Citrea testnet phase, data availability usage once accounted for nearly 10% of Bitcoin's monthly data bandwidth, indicating that Rollup could have a substantial impact on Bitcoin's block space.