The time when it was most useful as a "BDD tool" was when I was working with an extremely technical stakeholder who was proposing behavior in a command line tool he wanted.
I simply wrote 'tests' that described the command line tool's behavior and showed the YAML to him. He corrected the mistakes I'd made by misinterpreting his original requirements and then I built the tool to that spec and when it passed I was confident I'd nailed his requirements.
QA picked up bugs afterwards but they were all either (quickly rectified) mistakes he'd made in the spec or environment issues. I had zero spec<->programmer communication issues even though (and here's the crazy part) the domain was very complex and I didn't understand it. It had to do with a highly customized software system I didn't understand which enacted some sort of financial process which I also didn't understand.
Cucumber can do this in theory, but in practice the spec is not sufficiently expressive and the stories end up being ridiculously, unusably vague. Unit tests could also do this in theory I guess, but good fucking luck getting a stakeholder to read them even if you do manage to write them "readably".
I'm taking this process a step further. Although these YAML specifications were useful for me in the past to collaborate with stakeholders they're still not amazingly readable. For instance, the "YAML inheritance" makes it easy for programmers to maintain but harder for non-technical stakeholders to understand.
Instead of sacrificing maintainability for readability I created a process to easily generate readable stakeholder documentation from the 'YAML tests'. I used this in the libraries on the website above to generate always-in-sync-and-still-highly-readable documentation.
I think this could be used to essentially write low level "unit" tests which generate documentation which stakeholders can interpret (e.g. defining the behavior of a complex pricing algorithm) and use that to get a quicker turnaround on understanding, defining and modifying desired behavior in complex domains.