To combat bots.
Lost Ark banned one million bots, but there are so many more bots to ban. Acknowledging the problem with gold farming in their latest news post, Amazon announced further action being taken to combat rampant gold farming. Foremost they are apparently working on systems behind the scenes to make it harder for bots to get into the game. How? No details.
More relevant to the regular user, apparently gold farmers were botting quests to obtain gold easy. For many of those quests, the reward is now silver instead.
We’ve also heard player concerns about the effect these bots may have on the in-game economy when it comes to gold buying and selling, and we are closely monitoring this situation. We have changed the gold reward to silver for some Rapport and Guide Quest rewards in order to prevent the abuse of these systems by botters and gold farmers.
More details at the news post below.
Source: Lost Ark