I may be wrong but from what I understood, it's more or less a way to manage AWS Lambda functions (cgi-bin scripts), Docker, and a MQTT client connected to AWS on your GNU/Linux devices (raspbian on a raspberry pi for example, or a x86 pc).
However you still need Ansible or similar to manage the device so the actual value is kinda low because if you have a setup to manage the device, it's not much more work to manage docker and a mqtt client yourself. About running AWS Lambda functions on a the device, I think it makes sense for AWS to check the box "IoT edge computing with AWS Lambda" but unless you have a huge codebase in AWS lambda, it seems to be a bad idea.
In one sentence : "vendor locked half baked IoT platform".