Yeah, to carry on from what @limited-rainbow-51650 said, the awsx is used to do certain complex compositions of things which normally would require a lot of extra resources to be created manually.
An example is the FargateService in awsx. It allows you to setup a lot of the ecs Fargate components with a single object creation, rather than having to do all the individual pieces by hand.
I've found it quite handy. Hit me up if you want an example.