Oh no, they are not. I loathe projects that only do mailing list support, because that means I have to subscribe to the mailing list, create a new folder and filter rule so that the mailing list doesn't flood my inbox with stuff I don't care about, and once the problem is solved, leave the mailing list, remove the filter and folder.
In contrast, issues on GitHub/GitLab or public self-hosted GitLab instances only require me signing up once (and in most cases via some form of SSO), I can add attachments such as screenshots or detailed logs that would just blow through the ridiculous size caps on mails, and I only get notifications on topics I explicitly subscribe for.