One major advantage over its predecessor is the first image: your workflow is defined as data instead of code, so you get a nice visualization of your workflow

One major advantage over its predecessor is the first image: your workflow is defined as data instead of code, so you get a nice visualization of your workflow state. Try reading SWF execution histories for comparison. Are you asking why you wouldn't just write your own coordination code and not use a coordination service at all? The advantage is scaling and robustness. These workflows can run for days/weeks/months, and each step in the workflow can run on different hosts that are optimized for that step. And workflow state is handled by AWS, and so is basic workflow logic (retries, timeouts, event logging, etc.). Unlike Oozie, Luigi, etc., your workflow state is not coupled to any of your infrastructure, so it can survive all kinds of crazy situations (fleets dropping offline, replacing clusters, etc.).