People spend a lot of time and money acquiring cards for their tournament decks, and it stings to have them taken away. Things are quite different today, now that Arena exists
You can get extra combat steps on landfall triggers and buff your creatures
Moana, Of Motnui Moana is the core of any Princess deck because she allows you to Ready your other Princesses every time Moana quests, effectively letting your other princesses Quest or Challenge without putting them at risk of getting Challenged back
Ice Age introduces a type of card that are termed by the fandom as 'cantrips', which are spells that cost 1 mana, draws you a card, and does something extra
Is Biosynthic Burst legal to play
They will be replaced by these more generically powerful pieces that also help you to find the right card for the situation