User blog comment:EmoTank/Theoretical Bloons Forms/@comment-4970029-20120426001707/@comment-4075144-20120509022032

If you think about it, it actually prevents someone from spamming X tower to defeat Leads/Armored. Some will always defeat them, like Ring of Fire, Dragon's Breath, White Hot Spikes, etc. It requires variety of towers, and of course there's always M.I.B.