Exactly this. I think this is pretty much the use case most people envision when they think about a container orchestration service (it was for me, anyway). My understanding is that EC2 and friends didn't deliver this on day 0 because efficient container isolation is hard.
Copy in the sense of the product features, not the product implementation. Joyent has long provided a "run your container as a service" which IMHO is the best way for a small/medium to run container services. The whole create VM's to run containers creates a lot of extra work. Plus this could be great for teams doing data analysis, just spin up 100 containers for 30 seconds type of workloads.
The OP is short on details anyways, does Fargate run on a tuned xen vm's or do they have linux servers under there (or maybe they're SmartOS ;) ).