This lets you cast powerful creatures for a reduced cost, even if they must be sacrificed immediately
Every color and archetype has access to some kind of card draw engine, and there are hundreds of options in Eternal formats like Commander
I think this kind of gameplay is really neat, and feels very Azorious
cEDH decks leverage their high life total and extremely low-mana curve decks to draw some thirty cards while 20-life formats like Modern rely on cards like Angel's Grace to survive a negative life total No matter when this is used, expect it to be unfair
Generally, it's not simply because they're the best MTG cards
As stated above, if you have a multicolored deck that has green in it, my tip is to lean your manabase more towards green and use some of the spells found in The Best Green Ramp Spells guide to fix your colors