It will only happen once, as Impending Disaster is sacrificed after the land destruction
Not only can these two modal DFCs be utilized in Historic control decks, but they also avoid the mana competition that fetchlands would create if they were legal
If players have any cards in hand that allow actions to be taken with them from a players opening hand, the starting player takes all such actions first in any order, followed by each other player in turn order
Everyone's budget is different, but the number of booster packs you'd have to open to complete an entire set is often well into the thousands just due to the sheer luck you'd need to hit the cards you're missing
That being said, theyre a very good one in one of the best color combinations for an enchantment-heavy deck
For just 1 mana, you can swap any number of cards from your hand with cards from the top of your library, then reorder the cards you put back on top