Ethereum is a decentralized platform that runs smart contracts: applications that run exactly as programmed without any possibility of fraud or third party interference.
In order to run these applications, Ethereum uses a hashing algorithm called Ethash, which is designed to be ASIC-resistant so that it can be mined by anyone with a regular computer.
The use of a hashing algorithm like Ethash is important because it ensures that the Ethereum network is secure and tamper-proof. Without it, anyone would be able to maliciously modify the code of smart contracts and potentially wreak havoc on the entire system.
So, in short, yes – Ethereum does use hash. And it does so in order to protect the network and its users from potential threats.