Re: 'Headless CMS' in the article: Since the introduction of the JSON REST API, I've been using Wordpress as the back-end to various personal and professional projects, built on various web and native mobile frameworks.

One of the good things about Wordpress is the familiarity to it from the people who have to use it. (Authors/Editors/Contributors). (Though, I'd say Gutenburg might stir that up a bit).

Also, once you learn how to write plugins, the sky's the limit really.