Both. The distinction between "professional" and "amateur" is solely whether one is getting paid for the work, which doesn't seem like a reason to differentiate on features.

DD should be about the image, not the artist and spotlight about the artists

Both, although leaning towards Amateurs too.
Amateur 3D Artists need/like the extra exposure, while being inspired by the interest in their work.
It's nice to read and know more about professional 3D artists as well, but information may be more readily available on them on the internet (they usually have their own websites set up, etc).

Both - not only pros can be incredibly talented and feature-worthy!