What are the advantages of BDD and Behat?

What are the advantages of BDD and Behat?
Best answered in the blog post by Everzet ( creator Behat, Mink, co-creator of PhpSpec)

"People get upset when software doesn't update often. This is usually because the systems around it, change fast. If Twitter changes its API, your twitter client must keep pace. If PayPal’s integration changes, your eCommerce shop needs to change with it. And even if no single integration pushes you to make rapid updates, you can be sure that your competitors will."

http://stakeholderwhisperer.com/posts/2016/3/valuable-products