Well, while reading at it. Bitcoin had been a challenger to paypal. Which is more useful and highly digitalized currency now? What do you think or which do you prefer? 
PayPal isn't a currency. There's no denomination "PayPal". It's merely an online account and a service, just like a Credit Card. if can be used to purchase goods and services over the Internet and is being used to protect consumers from fraud and scams. Bitcoin, on the other hand, is a currency. But it needs services like PayPal!