We have to face some difficulties when we try to use crypto currencies instead of regular currency widely.We could find still more people being illiterate in most countries who are still unaware of digital transactions and they don't have a credit or debit card.The only thing they know is fiat currency.More over,internet has to be widely available to use crypto currencies.But the best feature about bitcoin is is decentralized nature due to which still governments struggle to gain control over it.People holding crypto currencies are their own banks and they are not in need of banks for transactions.