Its flying and vigilance (it can attack to deal combat damage without tapping) made it a force to be reckoned with in both offense and defense
(Bevy of Beebles), Rings a Bell, Underdome Notable reprint: Cheatyface The Blue Deck from Unsanctioned Black Deck List New cards: Acornelia, Fashionable Filcher, Infernius Spawnington III, Esq., Bat-, Underdome Notable reprint: Booster Tutor The Black Deck from Unsanctioned Red Deck List New cards: Boomstacker, Stet, Draconic Proofreader, Abstract Iguanart, Underdome Notable reprint: Goblin Tutor The Red Deck from Unsanctioned Green Deck List New cards: Pippa, Duchess of Dice, Surgeon ~General~ Commander, Spirit of the Season, Underdome Notable reprint: Timmy, Power Gamer (with new art)
Also, it gives opponents an option on how to pay Phyrexian mana for their creatures to attack
Living weapons on the other hand create a token creature when they enter, the Germ tokens have no toughness and would die on their own, while For Mirrodin
The difference, though, is a special holo pattern on the text area of the card