As a rule, drawing cards is tempo-negative
Snow White could be great in a deck filled with Seven Dwarfs, but the average Rise of the Floodborn booster contains approximately 0.5 Seven Dwarfs, which means that a typical Sealed Deck only has three of them
(If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.) If Maester Seymour is no longer on the battlefield when its first ability resolves, use its power as it last existed on the battlefield to determine how many +1/+1 counters to put on the target creature
Others, like me, are simply intrigued by the ridiculous excess of his craft
Enlightened Tutor may get you an enchantment or artifact for a single mana, but you lose a card (the tutor), and you still need to cast said enchantment or artifact
Atraxas Fall also acts as a Plummet, so there an extra bonus to make up for it being a sorcery rather than an instant