Eh...lets you play turn 3 Stoneforge Mystic with some protection and doesn't afraid of anything.
Also...snap Spell Pierce Brainstorms and Ponders from RUG delver as a good player knows how to maximize value from Brainstorm and Ponder. Sure you side out some Spell Pierces against RUG delver, but its pretty vital to catch their card filtering.
Spell Pierce is also not completely dead against Maverick as you can still Spell Pierce Green Sun's Zenith and catch a Swords to Plowshares when they get greedy.

