I've had some trouble finding any use for Coppersmith. It seems like basically a very swingy dead card to me. Anyone have any tips on how to use it so it's actually decent/good?
Swingy? No, it's really not swingy, because you basically shouldn't be buying it at all in situations where its payload is uncertain.
Coppersmith does only one thing: Give you a lot of money in the right circumstances. So, this is actually a more limited ability than you would think, because cards that give you a lot of money when you play them are deceptively bad. You actually want to do other things with your cards, like attack your opponents, trash down, etc. Okay, of course you do need some money at some point and this does that, but it only does it really well if you basically draw your whole deck and have a lot of Coppers. These work against each other, because it's hard to consistently draw your deck and have a lot of Coppers; usually you trash your Coppers so you can draw your whole deck. So bottom line here is it's usually pretty bad as a money source in engine payload. Compare to Bank, which is oodles more expensive, but isn't a terminal, and works with every Treasure, not just Copper, and still isn't like a really essential piece of an engine, often you do just fine with Gold or Platinum.
Like most cards, Coppersmith can shine in the right combo situation. It's pretty good with IGG... reasonably often it will be the terminal you want to pair with IGG. And Apothecary.
But on the whole it's not a very good card, no.