1.The essence of currency is a value anchor. When you pay labor or produce something, the market will naturally give you a price corresponding to your payment (value manifestation)
2.The essence of currency is liquidity. For legal currency, it is done by the bank. His transmission medium is commodity circulation and capital circulation.
3.The essence of currency is credit, which is more effective for world currencies or super-sovereign currencies mentioned in forums.
4.
Musk said that the essence of currency is a commodity that can serve as a general equivalent.
5.I may also say that the essence of currency is rights. Whoever has a strong fist, whose weapon is advanced, whose technology is advanced, whose country is powerful, is what he says, and everyone must abide by it.
I agree with what you listed. These things are all possessed by bitcoin. However, it still isn't counted and acknowledged by the government as a currency. Perhaps because they have their own local currency in fiat in the first place. Since bitcoin and other crypto aren't issued by the central organizations, they aren't accepted as such.
Currency functions as an anchor of value and as a commodity in general. Many countries have their own currency and what they have to do is to sustain, maintain, and boost their economy to retain its face value in relation with dollar. Although the problem with traditional currencies (physical money) is that it is prone to inflation. Meanwhile, crypto is lesser prone to inflation which makes it a better option to store funds.
Hopefully, the countries all over the world will soon notice that bitcoin and other cryptocurrencies are currency because it can also do what fiat can do.