Something people often overlook when comparing Paypal to Bitcoin is how much easier it is to get started using Bitcoin. With Paypal you have to give up all kinds of private information and to really use it fully you have to tie it to a bank account. Even if you don't care about privacy, the hassle of getting started compared to Bitcoin is a factor.

Then on top of that there issues when sending money internationally, chargebacks being at Paypal's discretion, Paypal being able to freeze your account for any reason, etc. The difference between Bitcoin and Paypal is already comparable to the difference between something like Netflix and Blockbuster, and Bitcoin is only going to keep getting better.