It doesnt make a huge difference in 2-color decks, but 3+ color decks love this for its low cost and easy fixing
However, it becomes excellent when paired with Mufasa, Betrayed Leaders ability, The Sun Will Set, which means that when this card is banished players can reveal the top of their deck and play it for free if its a character
The Deck (the original deck which personified the card-advantage strategy) packed the Tome as a way to gain card advantage steadily throughout the game
The chase Traveling Chocobo variants, for instance, are exclusive to Collector Boosters, as are surge foil and extended-art cards
By making them both uncommons that green-black was happy to play, the cost to put them in your deck was low enough that you'd take them both, and then it's time to Ragnarok and roll