What is Data Offloading in a distributed system, and why is it used?

Data Offloading means moving large payloads OUT of the primary message/event itself and into cheaper, purpose-built storage (like S3 or a blob store), replacing the payload in the message with just a reference/pointer to that storage location. It's used because message brokers like Kafka have practical size limits and cost characteristics that make them a poor fit for large binary blobs (images, big JSON documents) — keeping messages small and fast while the actual data lives elsewhere.