BTC & ETH are both digital currencies, but the primary purpose of ether is not to establish itself as an alternative monetary system, but rather to facilitate and monetize the operation of the Ethereum smart contract and decentralized application (dapp) platform. Ethereum is another use-case for a blockchain that supports the Bitcoin network, and theoretically should not really compete with Bitcoin. However, the popularity of ether has pushed it into competition with all cryptocurrencies, especially from the perspective of traders.