A lot of these cards also are staples in the most popular (and powerful) commander from the set, Vivi Ornitier, further increasing the price spike
Rydia is even a discard outlet for Yuna, Hope of Spira, so someone gets to live the dream of discarding Bahamut for Yuna to reanimate
It will simply be easy and consistent lore gain, if you can keep up in cards (gee..there's that A Whole New World again!) Belle will be a much more consistent finisher than she was in the past, and will finally be the staple in any competitive Sapphire list
The disappointing size of the packs, the overall number of cards in the March of the Machine: The Aftermath set and the fact that they were no cheaper than standard boosters, meant that they didnt sell well, and consequently, these story-based booster packs wont be revisited
Don Karnage is also a great target for Pluto, Friendly Pooch