I'm glad they are _finally_ solving the multiple desktop issue, its definitely the most frustrating aspect of OSX. Also, loved how it worked with AppleTV.
With regards to the last point - privacy from your identity provider -- isn't that somewhat moot for most sites as they have those facebook/twitter/google+/etc share/like/plus icons that report back anyways.
But a compromised credit card doesn't mean you risk your whole bank account. First, at least in the US, there are limits to what you are liable if you are card is compromised -- report within 48 hours, the limit is $50, report within 60 days, the limit is $500. Second, credit cards have a credit limit -- so, worst case scenario, you'd be out to whatever your limit is (which is unlikely to happen as any weird use of your card would probably trigger it for a security review, which wouldn't allow any transactions until someone talks to you). Finally, credit cards (unlike debit cards), are not linked to your bank account.
But, almost no one seems to offer a discount for cash - which they pay 0% on and they don't have to wait to collect from the credit card companies.
There are so many of these alternative payments systems available nowadays, but none seem to really offer any benefits (or protection or increased warranties) to me over a credit card to change my personal purchasing behavior.