How a escrow would be better than the wallet system we already use?
I've a similar suggestions to my service. In most cases, an escrow system means money refunding when purchased content has been detected as scam. This is an additional buyer protection from the trusted service. For example, when verified seller upload a faked content after his verification.
There are no fake contents, all images are verified and after the verification the sellers are only able to edit things like price, title and description.
Also, in that case, if the buyer find something that is not correct, it is our responsibility to refund them, since we're the ones providing the use licenses.