What you did is much more effective than leaving any feedback.
Most sellers do not sell at auction. We use Fixed Price listings and only meet our customers when they have purchased. And only then can we read feedback.
Your UID gave the deadbeat a Strike. Sellers often have an automatic Block against bidders who have Strikes. You can put this in place through your Seller Preferences. Blocks mean the deadbeat can't even bid, never mind win and refuse payment.
Not that the deadbeat can't leave feedback either. Count your blessings on that one.
As a side note, when sellers could leave negative feedback, some went ballistic on deadbeats. And then new customers, who have the leisure to read FB and assess the seller, would say 'Whoooah!' and backbutton away from the seller who was presenting himself as a suitable candidate for an anger management course.
Not leaving FB is a protection for those sellers.
FB is voluntary.