BFT is essential in blockchain and distributed ledger technologies, where nodes may behave in unexpected ways due to failures, network issues, or malicious actors. A system with BFT can tolerate up to a certain number of faulty nodes and still reach consensus and maintain the integrity of the system. In the context of cryptocurrencies like Bitcoin and Ethereum, BFT helps ensure that the blockchain can reach an agreement on the state of the ledger, even in the presence of network issues or malicious actors.