I've always sort-of-joked[1] about a "Blood Standard": your status as reserve currency is proportional to the percentage of the world population your nation can murder in 12 months.

Puts a hard floor on nations with strategic nuclear deterrents - they can never fall below a fairly high threshold, no matter how much of a "Security State Zombie" their national economies have become.

[1] I'm not 100% sure it's all me joking anymore.