Why would you use this over diagrams.net/draw.io, which integrates with far more tools (Google Apps, Atlassian tools, Sphinx) and can take text input (Mermaid), and embed editable copies in other file formats like .svg/.png?
The target audience of this tool consists of application developers that want to create new applications that require their end users to author graph like structures. They can use this tool and avoid re-implementing basic interactive features like drag & drop, panel management, zooming, undo/redo, etc. Examples of such applications within AWS would be AWS IoT events & AWS IoT Things graph (existing customers), AWS Step functions, AWS Cloudformation (not using the library as of now). Examples of such applications outside AWS would be: https://www.stackery.io/, https://www.voiceflow.com/, https://parabola.io/, etc.