User blog comment:DaNASCAT/Introducing New Moderator Opportunities For Community Administration/@comment-1515612-20160113235354/@comment-1370845-20160116000853

"If you trust someone to edit your JavaScript, why don't you trust them to delete content?"

Because you can block them if they vandalise JavaScript and don't have full sysop rights. If they do have full sysop rights, they can just unblock themselves. Other than this, simply because they're new, or because they're only popping in to make a few MediaWiki changes and then leaving shortly after.

"Trust and good faith is what good communities are built on - If you can't trust a user with a number of rights, chances are you should not trust him or her with any rights."

It's not about not trusting, it's about trusting them with rights to the MediaWiki space without other rights. There are plenty of cases where a bcrat would be hesitant to trust a new user with full rights, but would have no problem giving them (sometimes brief) MediaWiki access.