There's several ways you can codify Jenkins pipelines, Groovy being just one of them. But ultimately it's secondary to the main design of Jenkins. I'm not taking anything away from Jenkins as a solution - it has been invaluable over the years. But the way we write, test and deploy software has changed since Jenkins rose in popularity and as such we need to rely on different workflows that utilise different tooling. While Jenkins can be used in that way, I'd sooner use something which was primarily designed to be configured via code and used docker by default rather than something that requires enforcement to follow those best practices. That doesn't necessarily mean Concourse, there's Travis, Circle CI, AWS CodeBuild and a bunch of others that all default to that kind of workflow too, but it does mean I'm unlikely to ever advocate Jenkins again in future jobs.