Well, it would also affect people who report bugs.
If you report it on some individual-dev's gitserver, it'll usually get ignored, as he is just going to look at GitHub. Also can't log in anywhere, with your Nostr signer.
Discussion
Or it's just extra work for bug reporters (which can be a good thing) compared to nostr issues. It's public and easy to submit, and not sequestered on the individual dev's server. Bug reporters don't need to make a bunch of email/password accounts to other dev's servers.