The three things that make life gain good are low mana cost, high life returns and instant life returned
Draft Boosters contained a fixed rarity distribution and were vastly outsold by Set Boosters during their final years
Having cards like this gives you more flexibility when you are limited on the amount of cards you can run (100 or 101 in the case of my MTG Aristocrats Companion Deck)
Where it gets truly strong, though, is playing those creatures that get arbitrarily large think Malignus, or Taurean Mauler and following up with instant speed Burn spells
You can find non-foil versions of all the cards from the Through the Ages bonus sheet in Final Fantasy Play boosters and Collector boosters
For starters, this is great with Evoke, since you get the creatures abilities up front, then again on your next turn