A card like Bolas's Citadel allows you to keep paying life to cast your cheap eggs and to find your other enablers, while being a good alternative wincon
Being able to manipulate this from multiple application allows magic players to keep on top of their collections
(Choose a creature with the least toughness among creatures you control and put a +1/+1 counter on it.) With heat, sand can form a delicate work of art
If an opponent gains control of your Vision and chooses to phase him out and the duration of the control-change effect expires before Vision phases in, then Vision will phase in under your control as that opponent's next untap step begins
If we can benefit from any spell as long as it can be played on their turn, I want to load up on all of the 75% spells I can to make sure we're pilfering their cards, thus getting us even more value
Not in the way that Black Lotus or even more recent cards like Uro, Titan of Nature's Wrath are