The US already has full control of the global currency, what could this possibly buy them? They want to be able to embargo nations' currency and destroy them do

The US already has full control of the global currency, what could this possibly buy them? They want to be able to embargo nations' currency and destroy them doing that economically, this would get in the way of that... They would need FB's blessing to properly deprive citizens of other countries whom they are targeting of financial resources. So obviously it's a non-starter.