In some sense, yes the ultimate purpose of a bearer currency in the era of government controlled custodial currencies is having a currency that the government can't seize from you or put prior restraint on you spending. Thus by definition, the main use case is "illicit".

But remember that "illicit" also includes sending donations to protestors in Canada when the government froze their bank accounts, or sending payments to dissident organizations that have been blacklisted and denied banking services, etc.

We can also say that the primary use case of signal is "illicit" communication -- that is, attempts to skirt eavesdropping by various government security organizations, and this is why Signal received funding from the U.S. government - it was a device to assist in coordinating anti-government protests in nations the US wanted to oppose. For the same reason, the U.S. Navy created and funded Tor.

So this is a two way street -- the ability to send payments and securely communicate even if your government doesn't want you to do that is great when they are used to support dissidents in nations you oppose, but not so great when they are used for similar purposes at home, or when they are used for organized crime. Just because a technology's primary use case is "Illicit" doesn't mean it's not a valuable or useful technology.

Illegal transactions are also 11-12% of the USA's economy.[1]

In 2019, forex volume was $6.6T per day [2], or $1716T per year. Meanwhile global GDP was only $87.5T [3]. In other words, almost 95% of global currency volume is speculation. Why would anyone use currencies that are mainly used for speculation?

Both the traditional and crypto economies are reflections of human behavior, but because crypto is more transparent, you can see it for yourself. And a lot of people don't like what they see. But it's not a new problem nor unique to new currencies or technologies.

[1]: https://www.investopedia.com/articles/markets/032916/how-big...

[2]: https://www.financemagnates.com/institutional-forex/executio...

[3]: https://www.statista.com/statistics/268750/global-gross-dome...

> Illegal transactions are also 11-12% of the USA's economy.[1]

Much of that figure are payments for untaxed, but otherwise legal activities. On the other hand, crypto figures are straight up payments for illegal activities.

> In other words, almost 95% of global currency volume is speculation. Why would anyone use currencies that are mainly used for speculation?

Much of that trading volume, speculative or not supports the international trade of real goods and services and hedges currency risk for large international companies [1]. The same cannot be said of Bitcoin, which does provide the same utility.

https://www.federalreserve.gov/econres/notes/feds-notes/the-...

Not really, the speculation has nothing to do with human behaviour. The conventional money system and the thousands of cryptocurrencies that copy it are inherently speculative and reward people for being indecisive aka being liquid. Liquidity is the ability to instantly change your mind and that ability has very little to do with human nature and more to do with the nature of your money.

Seems like you will get your wish as the trend is leading towards a future where only approved transactions will be allowed.