Hello,

Thanks for your report. I have checked and it is not a bug. Indeed, this option is to manipulate the value shown when you press the payout value of any post. By default, even if it is confusing, the $ sign does not stand for USD (Same for most of the Steem frontends). It stands for the current payout in Steem currency.

However, if you press this value, a popover will pop up and will show the payout value in the currency you've checked in settings.