Fiat and cryptocurrency are the same
To begin with; i will like to inform you that fiats and crypto currency are not the same; they obviously can be used to serve the same purpose; but they are not the same. I say this because fiat in cash or your bank account adds little to zero value if kept for a while or if converted to a higher currency for international trade. Meanwhile; crypto currency is a lifestyle where you can get profits or losses; wealth or rekt;
nothing fiat can purchase bitcoin can't purchase, so no difference between both because all are currency.
Bitcoin cannot be used to purchase everything; because locally, fiats is more accepted throughout the world; meanwhile if you are a digital worker; trader etc; you can ofcourse get reward and payment in bitcoin. Both bitcoin and fiat are currencies; serving different diverse importance to the world