Paying for an escrow service for every small transaction seems darn expensive.
As a seller, I don't have to implement PCI compliance, deal with an acquirer bank to process transactions, fraud checks, whatever - I link up the Paypal/Stripe/... account to my shop and that's it.
And as a customer, I don't need to trust Joe Random's webshop with my CC details, and I have a reasonably well working customer support when the seller turns out to be shady.