This is rarely mentioned. Because of its design, Starship can't just go to the Moon, it first requires orbital refueling (from other Starships). NASA estimates they would need at least 15, but that was before the Starship payload capacity was downgraded.
Starship's payload is larger. If they reduced Starship's size and used the extra mass for a second stage, then they could get to the moon in one go the way the Saturn V did, but they're really committed to getting that giant hunk of steel onto the surface of the moon instead of a much smaller and more specialized lander.