User blog comment:Cristina7/Introducing Discussions, a New Platform For Engaging Your Community/@comment-94.140.120.202-20160908222419

And as soon as the structured data stuff is ready categories will become superfluous. And the next big update after that is going to remove the source-editor.

But wait, that means Wikitext and MediaWiki itself certainly won't be needed anymore either...because every bit of content can be migrated without issues and every use-case can be easily satisfied.