I have to think that a Mint on one of your early Tac turns would have been useful to trash down your Coppers and Silvers. You want to either have Tunnels in hand when playing the Tactician or have Golds in hand when not, and both of those things are easier if you have fewer other Treasures clogging your deck. Even if the Golem can't flip your whole deck, you still get a benefit from Minting a Gold each turn.