While most precons come with the necessary Sol Ring and Arcane Signet, plus a handful of slower mana rocks, they wont hold their own against any deck running Ancient Tomb, Grim Monolith, and many more of the game changers that infrequently come from precons
Raptor Companion: Limited vanilla creature
During the night, cards with the nightbound keyword become more powerful
Starting with the Alara block, booster packs for both Core Sets and expansions began to contain 1 land, 10 commons, 3 uncommons, either 1 rare (7/8 chance) or 1 mythic rare (1/8 chance), and either a tip card (which explains the new rules in the set, such as exalted in the Alara Block or Infect in the Scars of Mirrodin Block) or a token (which is of a type produced by a card in the set)
I don't think it's very fun, but it might be good
There are plenty of other reasons, and I could go on and on