Arena is running one of those deals today where you can trade in 50 coins for 550. Players also have the option of trading in 10 gems (roughly half a U.S. cent) for the same amount.
500 coins is enough, for example, to enter a Standard or Historic format Event. Or about half the cost of on 8-card pack of Standard or Historic cards.
I am not sure whether this promotion follows a pattern or what. I've seen it mentioned in memes about the game so I guess that it's fairly frequent?
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Can you trade those coins back to FIAT?
Not too easily. Once in a while there tournaments with fiat money prizes and IIRC the entry fee might be payable in coin. Even then, to be sure of making any money one would have to be a really strong player that already had a good deck.
Then again, I've only saw that once so far and maybe you had to enter with gems? E
So — long and short of it — to downgrade to fiat they really make you work at it. 😃
As a casual gamer it does not seem worth it, compared to other games available out there
I don't disagree about that. I play mainly for love of the game, the artwork and the sound effects. :)