What would stop someone from setting up a bunch of accounts and selling a bunch of non-existent stuff? Is there escrow of some sort?
More details: http://www.bitmit.net/en/info/13/bitmit-bitcoin-treuhand-die...
For intangible goods, you simply need to show proof that the item purchased is intangible.
Paypal isn't perfect, but if it really screwed over merchants the way you suggest they do, they would have gone out of business years ago.
I don't think you can draw that inference unless there is a good non-Paypal option that doesn't screw over merchants. Getting a traditional merchant account and accepting credit cards online isn't such an alternative--that screws over merchants on charge backs and with the occasional massive and apparently arbitrary increase in reserve requirements.
There are plenty of studies showing that customers spend more if they pay by credit card. In fact just having a credit card logo visible will increase spending, even on cash puchases.