Re: convenience of paying
I quite agree that I have no interest in giving out personal info, particularly credit card info, to websites all over the place. Any model that needs this is going to fail.
And from the (legit) website owner's POV, I don't want your details either (unless I'm selling stuff): its just a data protection nightmare with no upside.
Using PayPal / Google wallet / Apple store or whatever as an intermediary payment system that can avoid you handing over such details is, a minimum, a must. They still provide some "leak" of contact details - perhaps they should start enacting web-only transactions as anonymously as possible (no postal address etc.). Hell, they might even do so these days - I haven't looked for ages.