As playing both is a little bit of a risk and you are going to play the better one you lump in that risk entirely on the weaker walker
Sure, many builds of Miracles play Dig Through Time now, but this card is not as essential as Senseis Divining Top paired with Counterbalance and Terminus
Serialized cards have already proven to fetch massive prices on the MTG secondary market
Future Flash is the Japanese SV4M product with its own card numbering, box format, and sealed-market behavior
When you swung with the first you could stack the triggers so the token churning happened first, and now you had 7 damage swinging on turn five, and 11 on turn six from the Hero of Bladehold alone, without any help
Note that's not colorless but each color which makes it to my mind the only Familiar that drops colored mana not colorless