Terraform's `for_each` meta-argument allows for dynamic instance creation based on the elements of a map or set, making configurations more concise and maintainable. It offers benefits such as enhanced readability, consistency, simplified data source iteration, and managing dynamic workloads. However, it requires caution when dealing with indexing issues and potential re-creation of resources due to changes in the input variables. The `for_each` meta-argument can be used with various types of inputs, including sets of strings, maps of strings, lists of objects, and even Terraform data sources. It provides flexibility and scalability compared to traditional `count` approaches, but its unique characteristics require careful design and planning to accommodate the nuances of this approach. Additionally, Spacelift is a tool that makes it easy to work with Terraform, including automating deployments, managing AWS credentials, and building complex workflows using policy as code and programmatic configuration.