Currently a grand total of 0 currencies are able to be used by 8 Billion people
Discussion
You mean to say nothing truly ubiquitous exists?
It’s an interesting thought, what tech does *everyone on earth* have access to. Fire?
Getting any life improving tech to everyone on earth is a noble / worthwhile goal. We shouldn’t forget how long and difficult that road is
What about preserving things like uncontacted tribes in remote wilderness?