The ability to use every dimension of language for personal use is the basis of verbal-linguistic intelligence according to Howard Gardner's Multiple Intelligence (MI) theory (1989).
If we break every dimension of language, as explained by the theory, we can extrapolate a number of major benefits that come as a result of having the ability to manipulate such dimensions to our personal, professional, and social advantage.
Let's begin with the first benefit, which is the ability to acquire and produce language. Polyglots and bilinguals alike already have one benefit which is that they do not fear the processes of decoding, connecting, and problem solving, whether they know it or not. This is because polyglots and bilinguals decode on an everyday basis. The ability to decode and make connections is what ultimately builds schema, or knowledge bases. The ability to decode, by itself, is a problem solving skill that applies to everyday life when we communicate, even in our own language. Take for example the well-known scenario of a Northerner and a Southerner speaking about the same thing in the same language and still not understanding what the other is talking about. Hence, if you have an inherent tendency to decode and problem-solve you not only carry it for language, but for Mathematics and other daily conundrums.
Language also consists on semantics, prosody, and pragmatics. This refers to the manner in which language is used to convey a meaning. Since language is worthless without meaning, imagine the advantage that people with verbal and linguistic intelligence possess when they happen to come across irony, sarcasm, or even plain lies. Investigators, lawyers, district attorneys, and criminal analysts are experts in prosody, pragmatics and semantics when they hear testimony. The intonation and focalization of language intends specific meaning which they, as experienced professionals, are able to extrapolate. This is because the human ear is primitive and easy to train to distinguish between real emotion versus fake emotion and between truths versus lies.
Think about teachers, psychologists, counselors, social workers, and even customer service professionals: their ability to distinguish the unique and salient traits that come from intended speech (fake, monitored, purposeful) and from casual speech (real, honest, natural) is what ultimately makes or breaks their social communication. Therefore, these careers also demonstrate the personal benefit you can get from verbal and linguistic intelligence.
Far from the cliche of learning languages to get better job opportunities, verbal/linguistic intelligence is essential for life; it is a powerful intelligence because it taps into the human psyche as it is. Everything we say, according to the major psychoanalytical frameworks from Freud, Erickson, and even Fritz Perl's Gestalt, comes straight from our thinking processes. Having the chance to identify, define and analyze words as their represent our thoughts is quite a unique ability that serves you personally by helping you to understand the person whom you listen to, and then by allowing you to concisely analyze the true message behind the words. This is why Gardner awarded this talent an intelligence of its very own.