If Tigra is dealt lethal damage at the same time that you gain life, she won't receive a counter from her ability in time to save her
Commander Minn, Wily Illusionist Whenever you draw your second card each turn, create a 1/1 blue Illusion creature token with "This token gets +1/+0 for each other Illusion you control." Whenever an Illusion you control dies, you may put a permanent card with mana value less than or equal to that creature's power from your hand onto the battlefield
Murktide Regent A true finisher in blue decks, Murktide Regent dominates games once it hits the field
Disenchant would get picked high enough and often enough to give the illusion of being worth a cube slot but it didn't see anywhere near enough actual play to seem like it deserved its slot and that is the nature of the sideboard style cards
Not only does the Elemental come with card draw, you also get to gain life, ramp, or deal damage to each opponent depending on how many Landfall triggers you make