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 c

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.