PayPal is a huge international operation, with over one hundred million account holders worldwide, so where it gets its 'amateur' tag from is quite beyond me.

Some of the smaller sites that ONLY offer direct credit card payments on their own site probably wonder why they don't do much trade. If a total stranger came up to you in the street and asked for your credit card details you simply wouldn't give them out, but some site owners expect just that. At least with a big operation I know they are going to have security protocols in place as to who has access to that information on their databases. I also know my details aren't going to be lying around in a downtown store, where someone has forgot to shut the window overnight, or left on a pc when it goes for repair at the local computer shop.
Tom is right about the foot traffic on eBay, but that has to be offset by the fact that eBay allows illegally described items to sit in direct competition with you on the same search page. They also have increasingly stupid rules that seem to want to alienate the sellers that provide them with their income. Their latest is a real gem, in certain circumstances customers can be fully refunded
without having to return the item to you.