Consider that know wordpress use http://core.trac.wordpress.org/ that is more difficult to use and there are reports anyway.
Also consider that as in WP and many other projects sometimes bug reports are opened by the one that reply to a support request in the forum. So the non-skilled are helping because reporting their issues and from there the community help to find the bugs.
Also to submit a bug report in Github is more easy then wordpress because of the issue template that we have.
Also often bug report are only issues with plugins or misconfiguration and not a bug of the software so have a first level for non-skilled that is this forum is the best way to have the more skilled to do what they do and help the less skilled to achieve the same result.