WRT get a credit card on file. Why would Facebook outsource storing payment information?
Have any of the big players (Google, Apple, Facebook, Amazon, etc) allowed you to pay with a third party payment provider?
Because others might be better at it.
Couple reasons:
First, I'm surprised that anyone would purchase with so little information. A photo/price doesn't seem like enough room to make the sale.
Second, the merchant loses the chance to upsell and/or retarget the customer.
What's the counterargument? That the conversion rate is improved enough to offset these downsides?
I'm guessing this wont do well for mainstream, amazon-style commerce but could find some niches like impulse buys, donations, tickets, etc.
You pay to get distribution for your ad and if it converts you pay 30% of the total purchase price on top of that.
They have yet to do so, and Facebook ads remain lucrative.