Tier 5 Winter's Mercy getting less pops than tier 4 Icicles

What exactly does the Winter's Mercy even do? I've been running a few Silas + Ice + bottom path Skywarden + 052 Bomb for moab/ BAD damage in CHIMPS and I'm a bit underwhelmed by the Skywarden. How is it that by the end of the game the x4x has more damage than the x5x skywarden? I feel like the skywarden adds nothing to this strategy and I'd be better off spending the 20k on the tier 5 plus the change on the other tier 3s and 4s on other ice monkeys or support, or even a popseidon. I really like the concept of the skywarden and the bottom path, but it just does not feel like it has a place in the game in it's current state.