LOL and BRB might be key communication elements in a texting, emailing, social-media-obsessed world, but they don't make for high quality communication or conversation. Sometimes you might not even know what your communicating counterpart is even saying to you. With communication becoming more and more diluted by technology an essential element in building strong, mutually beneficial, and even profitable relationships.
It's an opportunity-making skill. Being a great conversationalist can lead to great opportunities, both in your professional and social lives. For example, to get your dream job, you'll have to back up your meticulously written resume with a great interview. The most comfortable interviews are those that feel like normal conversations--a give and take between two (or more) people who genuinely want to learn about one another. Once you get the job, your conversations with your new colleagues will help you gain their trust and build a rapport that helps you (and them) succeed.