If the world obeyed the Lord, the nations would use precious metals and fair barter. Just weights and measures are mentioned more than once as is not charging brothers interest . The most wicked people took over the economic controls of all financial institutions just like mafias promote gambling and prostitution/trafficking. Gvts have an industry of wars to farm, manufacture and sell drugs,ie Afghanistan. All of the above and more are contrived and controlled by the villains of this evil world.
Look at the temples they put on the $s.
I don't think it's sinful to use their system of money, like cash/ frns, but someday; perhaps soon it will become the difference between a commitment to the beast/ antichrist or not.
I have a LOT of problems with the current systems, every one of them.