Hmmm. You raise some very valid points, neko. I'm pretty sure, though, that I'm "in the clear" to use my Dalek picture in the way that I am. It would, as you very rightly say, be a different matter if I were to use it as an illustration in an SF story, even if I didn't use the name Dalek.
It reminds me of when Virgin books lost the rights to publish "Dr Who" books, but continued to publish the adventures of a character called "Bernice Summerfield", who was a former (book) "companion" of the Doctor. They could no longer use enemies like Daleks, but they found ways around it by doing things like having illustrations showing
people being killed by "death rays" with a "sinister sink plunger" just coming into view on the very edge of the picture
.