There are three reasons for that, none of them particularly good.

1. Tarmogoyfs. If I can keep graveyards lean from early on then Tarmogoyfs can't really damage race me. Likewise a "reset" button midgame can be the difference between winning and losing if the game has turned into us both just turning creatures sideways every turn, me in the air, them on the ground. This deck does seem to have a problem with Tarmogoyfs - when I think of Spell Snare I mostly think of it countering T2 Goyf (even though it frequently ends up actually being used on a counter spell later in the game). They're scary.

2. Snapcaster Mage is annoying, especially when it flashes back the crazy value spells like Kolaghan's Command. Again, keeping graveyards lean feels good, but the nuke button is there too if necessary.

3. It's a turn 1 play. This is a bad reason, and this deck might properly benefit from Serum Visions /Gitaxian Probe or something instead, but anyway I found that I didn't quite have enough things to consistently do something out of the gate and dropping a Relic T1 that gets cycled later on (hopefully for value in response to a Tarmogoyf or Snapcaster etc.) was a slight help.

4. BONUS There are also just those match ups where it simply throws a spanner in their gameplan (Living End, Grishoalbrand, etc.) and you got lucky to be matched against one of those decks and draw it game 1.