You can better use paypal by online payments you know because the bitcoin is not very trustable when you try to do something on the internet you know and paypal is
many times secured than the paypal ever will be
If bitcoin be used for online payment, we must looking for trustable sellers because bitcoins is irreversible payment, it is mean we can not take back the bitcoins if there is problem with goods that be bought. So doesn't mean bitcoins is not very trustable but the sellers who are not trustable.
That's why we need a system to take of those things because it is tough to guess who is trusted and who is not. Also, there is not guaranty that now trusted guys will not cheat later on so the system should take care of those things. As of now, PayPal is a good option to buy from unknown persons online and use bitcoins to deal with only know people.
Yes you are right we need system to take of those thing, but doesn't mean bitcoins is not trustable, personality i more like skrill and neteller than paypal. They have fast respond on costumers services although skrill and neteller are not too popular on my area.