Its second ability is also very titan-cycle-esque, stating that whenever Blight Titan enters the battlefield or attacks, mill two cards, then incubate X, where X is the number of creature cards in your graveyard
Standard only uses two different strong dual land cycles per year, and some more budget options like Gates and gain lands, but with only two years' worth of cards, there just aren't many options
The issue for cubes is that the best card for an archetype is not always the best card for the cube
The effects on these cards are extremely powerful, and can easily turn the game in your favor for no real in game loss
Tasha provides card draw and exiles instants and sorceries to be used later with her negative ability
This last part is perhaps the most relevant to the average Commander player