- being a good anonymous currency
- being a truly global currency for irreversible online transactions
- being a currency that's easily programmable
That's the three main use cases for Bitcoin. There are contenders for #1 (Monero, Dash), and for #3 (Ethereum). For #2 it's still the easiest because of the huge network effect behind it.
Traditional currencies can't compete with crypto for neither of the space. They are attached to systems that prevent transactions from being anonymous, global, irreversible or programmable.