Anyone read the invitational? Finkel's first turn with Dolan's World champion deck:
City of Brass, Black lotus, Mox emerald, Serra angel.
"Good luck, pal"
Rubin lost that game.
Need another example? Finkel, again, in the same tournament, with 3 moxes in play:
Obliterate. Cast mox pearl, mox jet, black lotus. Sacrifice the lotus, add 3 black to my pool. Yawmoth's will. Replay the other three moxes, the lotus, and tolarian academy. Mind twist you for 6(all rubin had) and stroke of genius myself for 3.
Needless to say, Finkel won.
Lotus is not NECESSARY for the deck, but it really hurts your speed if you don't have it.