I'd guess their main work and IP at the moment revolves around the devops and autoscaling parts. Defer's main value proposition seems to be in the reduced workload on developers and their infrastructure team (if they have any).

If you are able to run and maintain a continuously integrated microservice on a kubernetes cluster (or something similar, maybe severless), then you really don't need Defer, as far as I understand it. There's already a lot of CI/CD and autoscaling open sourced.

I haven't tried it yet, but I guess most of the "runtime" is already open sourced, otherwise the background jobs can't run locally...