Vitalik Buterin explained that partially stateless nodes validate blocks statelessly, avoiding full history and Merkle trees to cut storage and bandwidthut storage and bandwidth

Quotes that support claims

The nodes would operate by validating blocks statelessly. This means they don’t require the storage of the full Merkle proofs or the entire blockchain history. They can selectively keep certain parts of the state up to date.

The system would also allow users to configure what data their node stores, like common smart contracts, tokens, or specific apps, using a simple onchain setting. Users wouldn’t need to store Merkle proofs (the complex cryptographic trees that secure blockchain state), as only raw data suffices.