Imagine you're playing Esper Control and you look at this opening hand: Temple of Enlightenment, Temple of Deceit, Polluted Delta, Swamp, Island, Negate, Dig Through Time This is a hand that you're thrilled to keep against an opposing control deck like Abzan or Blue-Black Control
In short, you want to balance the mana value of your spells to ensure you have effective spells to cast throughout the game
To a 2/2 that attacks twice and doubles damage, so effectively an 8/2) -Protection (You want him to be really hard to kill even though he has regeneration, plenty of removal still has "This creature cant be regenerated" slapped at the end of it
With the set focused on Indiana Jones-style ventures into long-forgotten ruins, it only makes sense for Magic to produce a new mechanic centered around new discoveries
Of course, in Commander games starting at 40 life, being able to drop it onto the battlefield in the first turn is going to be a pretty massive advantage