Vitalik Buterin replied to a netizen X, saying: 'The key thing we are really early on is L2 being able to afford it. Since 2020 (if not earlier), I have been saying that only when transaction fees are cheap, the entire 'not just high-value DeFi' part of the crypto space can function. It wasn't until March of this year that they truly became a reality. If you ask me to choose the second and third early areas, they are: 2. ZK-SNARKs and use cases (such as zupass, railway, 0xbow, rarimo, etc.) are finally approaching maturity. 3. Account abstraction. ZK-email (and zk-wrapper similar to centralized ID) is particularly important as it connects the two.'