Hi Vendelhelm,
to be honest, Ghost Bane is the only weapon I ever painted in that size. I just wanted to try something new and had a bit of spare time on my hands.
The rest of the weapons have been painted in this format:
Painting in this size is -in my oppionion- sufficient for the small final icons in the game. Scaling down large images can even result in a lower overall quality. All the downscaled details can make the final icon “noisy” and hard to read.
Cheers