Draft play is a format in which players open fresh booster packs, draft cards in a group and compete with the decks they construct from that draft
All permanents you control phase out. Being phased out means that nobody can interact with your permanents in any way
The beauty of split cards, unlike double-faced cards, is that both sides are always accessible at the same time, regardless of where the card is
This keeps your deck churning and helps you to dig for win conditions or essential pieces, especially in combo decks
(At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
The same was true for Mantle of the Ancients which features another unexpected callback