It means you pay less ink to play it, it doesnt reduce the ink cost value of the card
If you wait until after the declare blockers step, because all combat damage is dealt at once, Yuffie won't normally deal combat damage
CEDH decks exploit this by dropping stax pieces, like Magus of the Moon and Thalia, Guardian of Thraben, but you could also cheat in big bruisers like Captain of the Watch
Vigilance is common among soldiers, but trample and haste are much harder to come by and valuable for pretty much any other commander on this list
Without Yawgmoth, Thran Physician, Golgari Yawgmoth would not exist
This doesn't have any gray tones in it to match this card being part of the Steel suite, but the gentle sunset (or sunrise) in the background complements Snow White's gentle expression regardless