You know, someone needs to write a page named "Don't use String, use C strings". I'm thinking that it could be done as a wiki page in the playground hanging off the
https://playground.arduino.cc/Main/ManualsAndCurriculum
page.
I agree that would be a useful addition to the Playground but, unless this is to be part of a more comprehensive document, the Manuals and Curriculum is not a great fit.
From Arduino Playground - HomePage
these are single sources that cover a variety of related topics. These could be used by individuals, teachers, and classes as stand-alone introductions to Arduino.
Unfortunately I don't see a perfect match but I guess User Code Library > Tutorials would be the best.