The reason for this is so that all tokens using the structure (which are most ICOs) can be built with the same specifications, making it easy for developers of wallets and other programs to easily implement new tokens into their products.
Some of these standards include:
- How tokens can be transferred by its owner
- How tokens can be transferred on behalf of an owner
- How to get data about the token
- Events data about the token
- Inquiring the balance of tokens at a certain address
- The total supply of tokens