First off, great design on your site; it's beautiful. Question: How's this any different from the HelloBar? Not that it has to be. Just wondering if it is.
To answer your question, yes, I would be interested in this product, and a lot of other people would be as well (most of whom are using the HelloBar). So is there a use case? The answer is yes.
How to improve: I would consider making options that are the size you show on the site and also larger. Something that slides down and looks beautiful and serves the purpose that a pop-up serves. I feel like this would be less intrusive than a pop-up (everyone hates them) and would allow website owners to show more info than a single line. So as you mention, an author could have a "drop-down" instead of a "pop-up" that shows their new book and entices orders.
The main function seems to be getting special offers in front of people without needing to alter the website dramatically. An example of this would be a company that's hiring but doesn't know where else to mention that on their page. So for stuff like this, it looks good, and the one thing I'd be interested in would be the option for a larger drop down that could show more than a single line but still looks beautiful (which your site currently does).
At the moment, it serves a very similar purpose to HelloBar. We also track metric such as the number of times a bar is closed, and I have some additional features to make the "action" in the bar more diverse (add options other than opening a URL). The actual Javascript component that runs the bar is very flexible and allows for some pretty deep customization-- not all of the options are exposed in the designer yet. Hopefully these features and some additional customization options will help ThreeBar stand out a bit from the competition and make it more enticing.
Thanks for your feedback-- I really appreciate it!
To answer your question, yes, I would be interested in this product, and a lot of other people would be as well (most of whom are using the HelloBar). So is there a use case? The answer is yes.
How to improve: I would consider making options that are the size you show on the site and also larger. Something that slides down and looks beautiful and serves the purpose that a pop-up serves. I feel like this would be less intrusive than a pop-up (everyone hates them) and would allow website owners to show more info than a single line. So as you mention, an author could have a "drop-down" instead of a "pop-up" that shows their new book and entices orders.
The main function seems to be getting special offers in front of people without needing to alter the website dramatically. An example of this would be a company that's hiring but doesn't know where else to mention that on their page. So for stuff like this, it looks good, and the one thing I'd be interested in would be the option for a larger drop down that could show more than a single line but still looks beautiful (which your site currently does).