Digital currencies rely, for security, on the seeming randomness of key pairs and other things.
That means, for example, that there must be no way for an 'outsider' to determine certain things about the transaction.
There is a public aspect of the transaction, which is not obscured by seeming randomness, and there is a private part of the transaction, which appears random, but obviously is not.
Anybody can look at the history of mathematics, and of cryptography, and see that there has never been a way to use anything similar to 'the appearance of randomness' to secure things a long time.
In other words the security of a currency must be based on a factual strength, rather than the appearance of strength.
Security, strength, based on 'apparent randomness' will eventually give way to a more practical security based on cohesive networks built around a common language, rather than 'trusting in the appearance of randomness'.
A language is not 'random' but a person cannot attack a language based coin unless they crack both the 'seemingly random' cryptographic part and also the language part. So if there are 100 language based coins, the most vulnerable will be the one that encourages the most offense against other coins, and most of the other 99 coins will have a warning when there is an algorithm hack, as well as a delay in vulnerability due to the amount of time needed to learn enough of the language to crack the currency.
Societies nowadays fall along a spectrum from 'fully traditional' to 'fully melting pot'. It has been a matter of survival for melting pot societies to come up with elaborate subterfuge regarding 'democracy', 'equality' etc to convince gullible people that their blob is superior to more natural societies.
It inevitably starts with force, 'we have guns, join us or die', then evolves into more subtle manipulations.
Ultimately though melting pots always produce the same sewage stew, a group of people disconnected from history, unaware of what they lack, being used by ambitious politicians and others who are after simple power and profit.
If you go to a real society made of people with traditions there is no economic sabotage or treachery at high levels. Those are things that are products of the melting pot.
Human nature has tendencies that can be sublimated in any direction. An indigenous society converts 'hunger' into 'hunting' for example, but a melting pot tries first to reduce 'hunger' to 'dependence', then sublimate it to some weakness that serves whoever has melting pot power at the moment.
As the digital economy develops, without the overt armies of fiat, the treachery and sabotage will eventually become the norm. The idealism of some coin enthusiasts is pleasant, but it ignores history and human nature.
There is no sensible way to build a digital economy, without using guns, unless it consists of groups delineated by language and culture, rather than by a shared history of conquest or ambition of conquest.
Until space exploration relieves the stress on an overcrowded world, trusting rivals to respect a shared currency is not wise.