Hitting the second effect here feels great, the third even more so
Then it's a mana sink for 7 mana to Giant Growth and trample-ify a dork you can target
Scion of Draco also fits multicolor decks pretty well, being able to give plenty of combat-related bonuses to gold creatures, and surprise, surprise, Leyline of the Guildpact also helps with these bonuses, extending them to all creatures including the Scion itself
Cargo-cult deckbuilding is when you copy a template because someone made a clean infographic, and you never ask what problem those numbers were solving
It's nice to be able to draw a card and proliferate by activating its 0 ability
Thats the kind of card that ruins games of MTG, but not for the person playing the card