Because the Unpaid Item Dispute process is more effective.
Instead of whining in a feedback, wise sellers open an Unpaid Item Dispute.
If the bidder still does not pay, he gets a Strike and the seller gets her FVF back.
But the Dispute is considered to end the matter and no feedback can be left by either party.
Most sellers have opted to an automatic Block of bidders with UID Strikes.
Keep this in mind.
85% of sellers use Fixed Price Listings. We don't meet our customers until they have purchased.
Of the 15% who still use Auctions, many opt for Buy It Now and don't meet the customers until they have purchased.
Most Auctions get bids only in the last few minutes of the listings, too late to react and don't meet the customers until they have purchased.
The number of sellers who have a chance to meet the customer before purchase is very very small.
Go to your Seller Preferences and enable the Block against bidders with UID Strikes.
There are a few other useful options there too, like demanding Immediate Payment on Fixed Price listings.
The only really useful feedback is the FB a buyer leaves for sellers. Watch for a lot of negs or neutrals. More important watch for a lot of polite notes about cooperation or fast refunds or fixing problems.
