I think that the question is, why wouldn't you? There are already a lot of work and testing done on projects that depend on 1.12 features, but using beta and rc releases. Final 1.12 version would just confirm that everything works, but without docker image, testing on staging infrastructure is delayed even the final version is out.

This is why I have https://NewReleases.io configured to track both Go GitHub releases as well as golang image tags on Docker Hub.

> I think that the question is, why wouldn't you?

We already have a reply to that in your case with the availability of the docker image.

In general, people do not rush into upgrading to a new release of any software because it's risky.

> There are already a lot of work and testing done on projects that depend on 1.12 features

The only reason I can think of is that you have a requirement to support TLS 1.3.

And there is no 'delay', as, surely, you plan based on the availability of everything you need (or build your own container image).

So you do not need it as you do not want to use it too soon. That is cool. Others may need docker image release aligned with regular release, and I think that there is nothing wrong with that. Especially for the people that are trying to contribute to Go by testing beta and rc releases.