Well, if you look at it that way: anything tangible that you hold in your hand that represents currency, only represents currency by conveniention. You're holding a lump of matter or a sheet of matter.
Discussion
Credit - Latin root cred “believe”
Specie - “in the actual form”
Specie in finance is gold coins. The thing itself.
₿itcoin is specie money. Not credit. It is the thing itself.