In that article, he shows that giving the coin to p1 (the 2nd player, it's 0-based) gives a /disadvantage/ to p0 (the 1st player), so it is actually beneficial for the player who gets the coin.
That might be true. The advantage that The Coin gives you is highly dependent on the deck that you have. In that particular deck that I used in the simulations, the advantage is rather large. For a deck consisting of stronger (higher mana) cards, the advantage is much smaller. I think it's basically due to the fact that a 2-mana drop vs 1-mana drop is much stronger than a 7-mana drop vs a 6-mana drop.
Yes, sorry I was referring to his numbers in the simulator rather than in the actual game.
In the game it depends on the deck - for some decks, it's more useful than others, either due to particular mana curves, or to triggered effects (the coin counts as a spell, so can trigger cards like Gadgetzan Auctioneer or Wild Pyromancer)
It was much greater before the extra card and coin was added.