ERC-1155 was introduced to improve upon earlier standards like ERC-20 and ERC-721 by allowing the management of multiple token types under one contract. This reduces the gas costs associated with deploying multiple contracts and simplifies the process of transferring multiple tokens in a single transaction. It utilizes unique identifiers for each token type, supporting both fungible and non-fungible assets in a single smart contract, allowing platforms and dApps to create complex assets more easily.