According to TechFlow, Vitalik Buterin replied to netizens on X: "The real key that we realized in advance is that L2 has finally become affordable. I have been saying since around 2020 (if not earlier) that the entire 'not just high-value DeFi' encryption part can only work if the transaction fees are cheap. It wasn't until March that the transaction fees were really cheap.

If I were to choose the second and third early areas, they would be:

2. ZK-SNARKs and use cases (zupass, railway, 0xbow, rarimo, etc.) are finally approaching maturity.

3. Account abstraction

ZK-email (and zk-wrapper for centralized IDs) is especially important because it bridges the two.”