It's indeed correct that with Bitcoin you can see your wealth grow, but comparing PayPal with Bitcoin in that regard isn't the right thing to do since PayPal is only a payment service.

People are using PayPal to complete purchases in online web shops, regular stores, peer to peer transactions, receiving money from certain jobs, and the list goes on.

Its main purpose is only to function as a platform to make it easy for people to transact with each other with security in form of buyer protection and such.