If your main repo lives on GitHub, your (primary) issue tracking is tied to GitHub.
But,github wanted to make this process easier for the people,hence they included issues,fork and PR model. It was easily done with intuitive interface without necessity of email for workflow, but if you have asked me, i would have issues,wiki,etc. integrated within repo just like Fossil VCS.
p2p is cool but not solution to this . gitea/gitlab/etc. already provide importing of issues with repos and if not,they must provide that feature.
This invokes the "it's not a bug, it's a feature" mechanism. E.g. Fossil has no problem integrating issues, merge requests, and wiki pages inside its repositories.
I just gave you example of Fossil VCS which has issues,PR,etc. baked into VCS itself.
Actually,what Radicle is doing is to extend git with p2p and not inventing new VCS with issues,etc. baked in.
What i am telling is that p2p doesn't solve this unclear problem and p2p isn't much beneficial to git.
And will there be enough peers to guarantee availability of repo ?
But GitHub does not mirror the issues/PRs from anyone, so it's a very one-sided connection.
This is exactly what radicle does.