I haven’t played the deck, so I have to ask: in how many matchups does Conjurer Mage tend to go to fatigue?
If it’s very few, then in most matchups, the milling itself does nothing to your draw odds, and you can just look at the expected number of cards that it gets you. Even if we assume 2 Power of Creation (some run 1), the expectation is just a bit more than 2 cards, for 1 less mana. And the probability of 0 or 1 cards is extremely low.
If more than 5% of games go to fatigue, then the potential milling is a concern, but I’m guessing that at least 95% of games are decided before the Mage draws their 30th card.