The Biggest Payments Network Wins
Just like Visa competing with Mastercard, they want to have the largest payments network in the world. They want as many customers as possible in as many countries as they can. In order do to that, their "payment network" needs to be scalable, fast, efficient, and secure. They must be competitive and accepted in order for customers to want to use them.
The same applies to sovereign nations and their currencies - In an effort to make a countries currency more desirable it's in their interests to ensure their currency is used for as many transactions as possible with as many people; on every platform, in every country. This gives value to the Nation's currency and increases their citizens standard of living and purchasing power.
As of now, the US Dollar is used for a majority of settlement and global payments - largely due to trade deals making it mandatory for use for energy (oil) purchases globally.
As the US uses its global payments network as a weapon to sanction enemy states, their enemies will continue to circumvent the payment network and develop their own; and with big manufacturers like China who can force countries who buy from them to accept their currency we no longer have an advantage.
Blockchain technology creates a perfect leap-frog technology for our adversary's to take advantage of if the US doesn't take action to get ahead of it first while it's still ahead.
Blockchain technology also creates a better technological solution for faster, efficient, and more secure global payments - preventing hacks and malicious actors. In the future, the currency with the best utility will eventually become the global payments standard.