This is one of those very interesting card in the hobby. It is unique and of a significance milestone for Pokemon. This is the first time where the 20th century modern art has been infused with Pokemon. Such crossover, bridges the gap between Pokemon and art.
As investment goes, I believe that this set will be of great value and return due to the following:
1. Difficulties in grading due to poor print quality
2. Difficulties in collecting all 5 cards of the set
3. Limited release in the sense of the time frame.
4. Popular choice of Pokemon
5. the relationship/linkage between each card of the set.