People use it all the time, it comes as part of Marketing Manager Pro. The thing to keep in mind is the Ebay Description Generator is designed for manually listing items.
What it does is you select a product you want a description generated for it then merges that products info into the template you select and rewrites the links so they link back to your site for the images and so forth. Then you simply copy and paste the HTML wherever you want, in the ebay case you would copy it into the description box.
You can see it in action as part of the Marketing Manager Demo which is on the left menu on
http://www.firetanksoftware.com
You can use it for ebay auction descriptions, newsletter description, general fancy descriptions. Basically if you want to make a quick layout based on your products data it can be used for that.