Ethereum is not just a digital currency. It is a blockchain-based platform with many aspects. It features smart contracts, the Ethereum Virtual Machine (EVM) and it uses its currency called ether for peer-to-peer contracts.
Ethereums smart contracts use blockchain stored applications for contract negotiation and facilitation. The benefit of these contracts is that the blockchain provides a decentralized way to verify and enforce them. The decentralized aspect makes it incredibly difficult for fraud or censorship. Ethereums smart contracts aim to provide greater security than traditional contracts and bring down the associated costs.