There are good VPN providers such as mullvad that accept payment in cryptocurrencies, but HN said those were useless... They also accept cash in an envelope if you are extremely paranoid.
Even if HN had a monolithic opinion on the uselessness of cryptocurrencies, your example illustrates a case where they are indeed not necessary, with the alternative satisfying even the “extremely paranoid”.
Cash has slower transaction speed (snail mail vs <30 min). Requires additional supplies to use (pen, stamp, envelope). It’s illegal in the USA to send cash in the mail. No way to get delivery confirmation without risking deanonymizing yourself.
https://www.snopes.com/fact-check/sending-cash-u-s-mail-ille...