Personally, i think it's completely plausible. The reason why I think that, is because product searches are, although more rare, are more targetted and specific. For example, a simple search for say "furniture" may be searched thousands of times during a day, but it's so broad that you may never rank in SEO or PPC for that type of search term. However, if you do your keyword research and find that there is a small niche for a specific product search, you'll find that it will be much more worth your while to bid of a keyword such as...."Bush Furniture Black Swivel TV Stand" (<--just an example). The above example might get a small search quantity daily, however, anyone who searches for it knows what they want, and hence has a higher chance of converting a click into a sale. Having said that, Conversion rates with product searches are much higher than standard category searches. Furthermore, because most of these searches are rare, you'll probably get a good deal in terms of how much you bid on your keywords. Therefore, i think that yes, promoting products is definitely viable and you should be able to make some sales by doing so.
If you choose the right keywords, you could generate some sales. You need to test and adjust your ad campaigns to find the profitable ways.