At the moment the escrow system is not 100% working and is something that i must work on in the next days. The agents hold the funds until the buyer confirm the delivery of the items/services. I will create a reputation escrow system through which, after each escrow transaction is confirmed, the buyer or seller can review the agent. It's a work in progress.
A "pay now" button that redirects the client directly to the wallet address is something that I think we must avoid atm, until I create seller categories that will have this option. In order to avoid scammers. The seller publishes a listing and the buyer takes contact via steemit.chat or email in order to review the details about the services/ the product. The seller can request immediate payment or deliver the services/ product and after that ask for the payment.
You must think to steemzon like a market, where you must interact with the seller, not just click a button.