If a project is having a difficult time specifying requirements BDD can help to derive better scope. I have quite a lot of experience of BDD in small and large companies. And have found that it does help where stakeholder's are pretty vague about what they want, BDD can help them think about the User Stories in more detail. Which ultimately helps to deliver the right product. You can also do the automated testing part too so you have automated acceptance tests which become regression tests after the feature has been released. However, I also found that it's difficult to get all the people onboard with it as it takes more time.
TLDR; Good if you have problems defining requirements, difficult if you have uncommitted stakeholders.