Crypto has nowadays three meanings. The first was cryptography, the second in currency as you describe, but the third meaning and most important one is related

Crypto has nowadays three meanings. The first was cryptography, the second in currency as you describe, but the third meaning and most important one is related to the latin root of that word in the sense of "secret", "hidden": https://www.etymonline.com/word/crypto- https://www.etymonline.com/word/crypto- When talking about something crypto, one must measure these two "secret" and "hidden" attributes. Signal was never really adopted because of its suspicious origin and strange adoption by whatsapp. Similar case for a few other messengers like Matrix if you get around to see that in more detail.