Stefan Kangas just announced that use-package has been merged into the emacs-29 branch. I’m inclined to take a conservative view towards moving packages into core Emacs, believing that a package should prove its worth and stability over an extended time before being considered for core.
The use-package macro has clearly met that standard. It really does make configuring packages simpler and the size of the configuration files smaller. Like many of our most useful tools, use-package was intended to make things a bit easier for its author, John Wiegley. He put it on GitHub and soon many people were using it and offering extensions. The :ensure keyword, for example, was implemented by one those users. Wiegley himself doesn’t use it because his workflow is a bit different.
The use-package package is a small thing but it does make my life simpler and I’m glad to see it get merged into core. Thanks to Wiegley, Kangas, and the others who made this happen.