The GitHub Checks API is a new, rich API meant to provide CI tools the ability to provide feedback into GitHub Pull Requests.

https://blog.github.com/2018-05-07-introducing-checks-api/

Microsoft App Center and Travis CI support this today, and Circle CI is preparing to release support as well. As you look for reasons why gci can go above and beyond what codebuild does, this would be a great way to show what is possible with a top tier integration.