Have to admit, as a fellow Go dev, with single binary static compiles, I don't really GET why I need docker... all it seems to offer is an increased workload and complicated build proc
Something like kubernetes also lets you abstract away the lock-in of your cloud infrastructure, so whilst it adds another layer and a bit of complexity, it again is arguably worth the effort if you're worried about needing to migrate away from your current target for some reason in the future.
As a framework it abstracts apps from infrastructure quite well. It's super easy for me to replace my log shipping container in kubernetes and have most things continue to work, as all the apps have a uniform interface.
Nobodies saying you can't build these things without kubernetes, but it definitely gives me more of the things than configuation managment systems currently do. Personally, I'd rather aim at the framework than handles more of what I need it to do.
Finally, bootstrapping a kubernetes cluster is actually quite trivial and you can get one off the shelf in GKE, so I'm not really sure why I'd personally want to go another route.
This is not revolutionary in itself, but having the creation and deployment of a server being 100% replicable (+ fast and easy!) on dev, preproduction, and production environments, plus it's managed with my usual versionning tool, that is something I appreciate very much.
Sure, there are other tools to do the same, but docker does the job just fine.
The problem of ensuring that upstream dependencies can be reproducibly installed and/or built is, of course, left as an exercise for the reader.