In reply to mark k..

@mark no need to apologise, it's a good debate :)

I just wanted to shift the focus a little bit as I think the critical questions aren't really that much related to database (or even backend) performance, but more so how and when WP API would be useful. Maybe there's a bit too much hype around it, it's definitely not going to replace classic WP templates, but makes WP a more flexible platform by opening up app integrations with it (be it a single-page application on the web or even native apps).

In our case the choice was made because we wanted to create a special visitor experience with a single-page application while having an advanced admin / editing interface with a rich set of plugins to do things like automatically taking care of creating / converting responsive images, etc.

This is not something which can be done in Ghost, and maybe there are other, simpler CMS systems which can deliver content via an API, but we were already using WP with a 100+ posts and wanted to use a proven open source system with a healthy ecosystem.

Maintenance is not something which our editors will do, one way or an other it'll be up for developers. But they should definitely be able to create content easily without having to worry about manually processing images or writing much raw HTML.