"The term imaginary property recognizes such contributions to society as the product of the imagination and is more productive as a starting place for discussion thereof"

No, it's derogatory. Very few phrases of the form "Oh, it's just your imaginary X" are designed to be complimentary. In common parlance, "imaginary" is just synonymous with "not real". The phrase "imaginary property" is designed purely to advance an agenda where people write books, create films, make software, etc all for some "manna" which, when pushed, advocates can't actually specify beyond saying "they'll find new business models". Yes, they will. Involving not writing books, films, etc.