Ethereum addresses are usually written as a hexadecimal string, for instance, 0x86fa049857e0209aa7d9e616f7eb3b3b78ecfdb0. This is not very readable for a human and would be very prone to error if you had to read it to someone over the phone, type it, and so on. It would also be easy to replace with another address without someone knowing. In fact, this is what has happened in a few ICO attacks. The Ethereum name service, or ENS, is a smart contract-based system for resolving human-readable names such as mytoken.ens to addresses. By registering an ENS address, compatible applications and wallets on the Ethereum network could map a readable name, such as MyTokenContract.eth, to an Ethereum address, similar to the way DNS maps domain names to IP addresses on the internet.

It is strongly recommended that any project built on Ethereum secures an appropriate ENS name. Not only does it look cleaner for users, but it will help to prevent hackers from using the name to attempt to steal from your users.