Not everyone in the world uses world reserve currency for daily purchases today. Do you think that will also be the case in a world where bitcoin is a/the world reserve?
Discussion
Yes.
Everything else is run by corruptible human beings.
Bitcoin is run by incorruptible math, physics, and code.
Over a long enough time line, everything else can only eventually fail; over any time line, Bitcoin can't.
Given enough time, the choice will be Bitcoin or nothing at all (i.e. starvation).
Maybe we can leverwge the math and physics to allow for local currencies that arent so easily corrupted. Ecash?
Its an answer to elasticity concerns.