Example : Against aggro, you would be wary about using City of Brass, even to play a valuable spell at a favorable time
That helps to actually reach the top end of your mana curve, rather than simply losing the game because you kept drawing the expensive cards that you couldnt castwhat we usually call mana screw. Its also worth mentioning that landcycling abilities do count as cycling for the purposes of cards like Jo Grant that trigger whenever you cycle. Also, since discarding the card is the cost and the tutoring is the ability, any abilities that trigger when you discard a card like Inti, Seneschal of the Sun trigger and resolve after you discard the card but before you search your library
Black I think the highlights in black come as cards that look and feel as if they were always in the old border, even though we know that to be untrue
Putting 5 charge counters on one of your Spacecraft might turn it into a creature, but that's only worth a card when you can use this as a trick
But for limited, probably huge
