Unfortunately, it only mills one opponent at a time, making this an inefficient choice for Commander mill decks
Looking at the most valuable cards in the Final Fantasy x Magic: The Gathering set as of the time of writing shows that the highest-value cards are all either foil or surge foil printings, which seems to have contributed to the hyper-inflated cost of both individual Collector Booster packs (now going for $100 on the secondary market) and a Collector Booster Display Box (fetching up to $1,200)
Thinking about picking up other collectables
So, some of those who want cards featuring a certain Pokmon will be looking for these to round out their collection
It started as an experiment, but Sephiroth is now becoming a core part of the deck
It also provides the option to draw cards, making it a perfect mechanical and thematic addition to the deck