Usually this would be negative for you and positive for the opponent. Nature decks, having lots of rares in hand and most times those rares being Ancient Sage (Legend keyword) means they have higher facilities. Also the player will seek to have higher facilities, as Nature decks are stock-demanding at first.
Also I would prefer to have Order of the White Lotus in my deck, rather than this card, and I would hate to summon it as a rare with the keyword. The Nature rare cards that are currently in the game are very good, and them being few means you can play them more easy. Furthermore they are expensive and so they are quite balanced.
So this card is not a very good idea