Milling your opponent is actually positive for them unless you can finish them off, and there simply isnt enough lifegain to enable Hope as a potential win condition
Its activated ability digs through an opponents library until it hits an instant, sorcery, or creature, and then it lets you cast that card for free
The card itself makes four 1/1 Hero tokens and then powers up every creature on your board, to reflect the story of summoning your adventuring party and imbuing them with the power of the crystals
Whenever Vincent Valentine attacks, you may transform it
There are a lot of characters from Snow White featured in Rise Of The Floodborn, including all seven dwarfs
Remember, I am not saying these cards are bad or will not see play in other archetypes, they are just not slam dunk includes for over 1/5 of the metagame, in full playsets, for every player running a certain deck