(this is probably unfairly cynical but), reading heavily between the lines, this reads to me like DHH noticed lots of Rails folks and rubyists already like and use "standardrb" for this https://github.com/standardrb/standard -- https://www.youtube.com/watch?v=QVilOzkLdlI -- but for some (unspecified?) reason(s), wasn't willing to bless the popular community-created universal standard as default convention, so instead wrote up his own, and is declaring his the default convention for Rails.