What is the main purpose of AWS Step Functions?

The main purpose of AWS Step Functions is to manage workflows across various cloud services. It allows developers to design and orchestrate complex workflows by integrating multiple AWS services into a single, coherent process. With Step Functions, users can define a series of tasks and the order in which they are completed, making it ideal for building applications that require coordination between different services, such as AWS Lambda, Amazon ECS, and AWS Batch.

For instance, in a scenario where a workflow involves data processing, you can use Step Functions to outline the sequence of data ingestion, transformation, and storage, while incorporating error handling and retries as needed. This orchestration capability simplifies the development of distributed applications by enabling a visual representation of the workflow, making it easier for teams to understand, manage, and debug.

The other options involve functionalities that are not within the primary scope of Step Functions. Building high-quality virtual reality experiences pertains to different services unrelated to workflow management, while message queuing is covered by Amazon SQS and similar services, and scaling distributed applications can be achieved with solutions like Amazon EC2 Auto Scaling rather than specifically through Step Functions.