Actually, the suggestion came from eBay store support. I had one of their consultants give me the idea. For the last month or so I have been keeping it in mind as I have done my own browsing. Perhaps it has been because I am looking for it, but I don't consider it a distraction as I still scroll down to see what the item is that I pulled up on the screen. However, if I don't see the showcase, I don't go looking for it, either, and I usually don't look to see if the seller has a store or anything else beyond a 3 digit feedback and a 99.0% or better score.
The problem is similar to when I was a small businessman and running advertising in a newspaper. I had to compete with the larger businesses who advertised with large ads as opposed to the smaller ones that I could afford. I started running ads that I thought were tasteful and effective. They might have been, but the customers didn't think so. We didn't get much action from them. When I started running ads that were meant to catch someone's eye, such as with humorous pictures or headlines, I had a much better chance to bring someone into the ad and make it all the way down to the "Call to Action" at the bottom.
I feel that my job in a listing is to both sell the item that I am listing, but just as important - or more so - to get someone to come into my store. I guess this is similar to a retail store showing something in their store window to interest the passer-by. With that tactic, they are more interested in getting someone to walk into the store and buy anything they find, not just the item that is in the window.