The intuition here is that the rules that block when CVC/ZIP doesn’t match necessarily happen after the bank already decided the transaction was okay, because that’s when Stripe learns whether CVC/ZIP match what the bank had on file.
So if you block on a mismatch, you’re throwing away an approved charge every single time since the bank already decided that other signals say the transaction is okay. The bank can block it themselves if they think it’s suspicious (which from my understanding wouldn’t increment this metric).