DeFi vs. banks explained

Decentralized finance, or DeFi, uses blockchain programs to move money without a bank approving each step, while banks hold deposits inside accounts they control. (ethereum.org, fdic.gov) On Ethereum, a smart contract is code stored at a blockchain address that “runs as programmed” when a user sends a transaction. Ethereum’s own documentation compares that setup to a vending machine: put in the right input, get the preset output. (ethereum.org) Ethereum says anyone can write and deploy a smart contract if they know the language and pay network fees in Ether. That is the “permissionless” part: there is no bank officer, card network, or app store reviewer deciding who may launch the service. (ethereum.org, ethereum.org) A bank account works differently. The Federal Deposit Insurance Corp. says checking accounts are transactional deposit accounts held at insured institutions, and deposits at those banks are generally insured up to $250,000 per depositor, per insured bank, per ownership category. (fdic.gov) Bank payments also move through managed rails. The FDIC says Automated Clearing House transfers are payment instructions between financial institutions that are batch-processed and settled by banks and operators such as the Federal Reserve or Electronic Payments Network. (fdic.gov) Banks are also required to know who their customers are. Federal customer-identification rules say a bank must use risk-based procedures to verify each customer’s identity to a reasonable and practicable extent before or while providing access to accounts. (ecfr.gov, fincen.gov) U.S. banks and payment firms also screen transactions against sanctions rules. The Treasury Department’s Office of Foreign Assets Control says it administers and enforces sanctions programs, and blocked property rules can require firms to stop or hold funds tied to sanctioned people or entities. (ofac.treasury.gov, ofac.treasury.gov) That difference is why DeFi users talk about “self-custody.” In a smart-contract system, the user controls the wallet keys and interacts directly with code; in a bank system, the institution keeps the ledger, provides the account, and can restrict access under law, policy, or fraud controls. (ethereum.org, fdic.gov, ecfr.gov) DeFi’s tradeoff is that the same automation that removes gatekeepers also removes many bank-style backstops. Ethereum notes that smart-contract interactions are generally irreversible, and TRM Labs said in its 2025 Crypto Crime Report that crypto transaction volume in 2024 exceeded $10.6 trillion while illicit volume still reached about $45 billion. (ethereum.org, trmlabs.com) So the cleanest way to read the DeFi-versus-bank debate is custody versus control. Banks offer regulated accounts, identity checks, payment reversibility in some cases, and deposit insurance; DeFi offers open access to on-chain code, but users carry more of the operational and security risk themselves. (fdic.gov, fdic.gov, ethereum.org, trmlabs.com)