If you give your opponent half of the 3 liner and they switch it with their wanderer lost soul then you can't rescue the other half. More importantly, consider this scenario.
Game is 3-3.
You give your opponent half of the 3 liner, there is one other soul in play.
You draw Son of God and New Jerusalem but have no defense left.
Instead of winning you now lose. If you had the 2 liner you could play Sog/NJ on the other half + the other LS, making it 5-4.