I don't know whether you remember when we were on the gold standard and what the Soviets would do to devalue our currency is to dump gold on the market. When we were in the Cold War, that vulnerability was pretty significant. Why create a single point of failure?
Yes our currency has many dependencies, but the benefit is that some of the bases can increase the dollar's value as others decrease it.
There's also an advantage in having inexpensive currency in that it makes goods and services more appealing to consumers.
Lastly, the biggest help to the US currency is if we would exhibit more fiscal constraint in our federal spending. More line item vetos please!
FYI