Bitcoin is different than PayPal so it is like comparing Apples to Oranges when it we're discussing about spending our own money on something. From what I know about PayPal is that they need to have another source in order to get their money. Bitcoin is basically like free money because if someone that knows how to make computers more powerful than it already is, they could build a Bitcoin Miner and get money from Mining Bitcoins and they would get whatever currency they want (PayPal doesn't have that feature).

Bitcoin won't overcome PayPal though Bitcoin will be a popular Digital Payment Platform.