If it becomes part of the stdlib, the update cycle will match the language. For now, improvements will come a lot faster as an external package

I believe the goal is for stdlib packages to be added with 1.19 once they have some real-world use. For now they're in x/exp to allow changes before that release.

They want to be able to break backwards compatibility, so they can experiment more. If they put it in stdlib, they cannot break it anymore.