The primary issue for me is one that I'm afraid is built-in to the game design... because the ONLY currency used is bitcoin, the game economy is pretty stagnant. NPCs can't buy your items because they don't have money to do so, because the developers can't just keep pushing real money into the NPC coffers. Because of this, players just collect tons of items they can't use and then they have no way to acquire bits except the extremely slow process of getting them from monsters (which, again, has to be slow because it would be unwise for the developer to just shove real money into that) or from depositing money themselves, or from getting extremely lucky and having an NPC get filled up by another player.
If items could be used in more complex ways, or rare items could be found that certain characters wanted, and then a character could run a small shop in the main village, it would encourage players to spend the money on each other, and to look for rare items to potentially sell so they could buy from others.
You'd have actual movement in the economy. I would feel a lot better about putting bitcoin into this game if I could potentially buy a rare item someone found or something someone carefully crafted after gathering tons of specific items...