User blog comment:Rappy 4187/Technical Update: November 9, 2016/@comment-5956954-20161109225433/@comment-1824272-20161110041441

The deprecated maps feature used MapQuest tile data for creating real-world maps. However, MapQuest ended its free tile API program, which broke all real-world maps under the deprecated feature. So they deleted all real-world maps and disabled the ability to create them.

That likely led to the need of using the MediaWiki Maps Extension for the creation of real-world maps.