From KDE Community Wiki

Qt Script & Digikam

Brief Description :
QtScript is a facility provided in the Qt Framework since Qt 4.3.
What it basically allows is to for any Qt or Qt Based (KDE) application to access all the internal Qt methods and objects of the application from an ECMAScript based language.

Relevance to a Developer:
Since it is not possible for the developers of digikam to cater to every request of the user community. But we as the Digikam team would love to cater to whole user base.
So, the Scripting interface will provide an easy to use API for anyone to write Digikam extensions without having to  be a digikam core developer.

Relevance to an End-User:
The end users would enjoy a Plethora of plugins which would enable them to do things previously difficult to achieve.
Like : (Use cases)
1. For all photos in which faces appear ( provided by the face detection and recognition Digikam GSoC project) remove red eyes.
2. Show all the photos where person A and B appear together.
3. Apply a Filter X to all images taken at a place Y. (using the Digikam-Geocoding plugin).