Personally I haven't met any recruiters who really care about only this.
Don't get me wrong. People appreciate open-source contributions but they'll look at repos etc and not just blindly look at the contributions bar.
Also I think github is not really good at surfacing PRs opened and merged into open source projects. It keeps getting it wrong for me under the 'repositories contributed to' section. Pinned repositories help with that a bit but still there's no way to showcase PRs and actual contributions rather than just list of repos.