Bitcoin has a high tendency of overcoming pay-pal, but for now paypal has covered large ground and grounded security under control as it is government backed up.
as bitcoin is spreads and as long as it can maintain invulnerability.it will supersede bitcoin.
In my country PayPal is not a very popular payment system. I can use bitcoin, but I can not use PayPal. Although this is a famous system, but it is not universally supported