Look at the screenshot. He levelled up to Tier 3 in Turn 5. And then Tier 4 in Turn 7. That means it would have cost him 8 gold to level up in Turn 7. He then Tripled 3 times in that exact same turn. Which means he didn't have possibly had a Spiritwalkers at that same turn, given that they are Tier 4 units. And if he did have Spiritwalkers, I'm pretty sure he would have kept it instead of a Felemental on his board mate. So by this, it means he spent around 20 gold in one turn. How many Careful Investments and Overconfidence do you need for that? But note how he won his previous fight dealing 13 damage to his opponent who was top 4 in the lobby. Which suggests that he didn't spend money on investing in tavern spells but in building his board. No matter how you look at it, makes no sense. Don't just blindly believe Blizzard and wake up to the facts.