Most buyers prefer to pay 25% more and buy the domain from Afteric/GoDaddy. So the website provides a showcase only for 99% of the time. It doesn't pay for itself, unless somebody sees a domain available and buys it at Afternic/GoDaddy (which I wouldn't know about). They pay the 25% more to remain anonymous, and to have the "security" of buying from a large recognized company. I've had buyers refuse to pay my asking price, but when the negotiations go sour, I put the domain on Afternic at twice my asking price, and they go right ahead and buy the domain at twice the price. Go figure.
Your own website is just one more tool in your sales arsenal.