Influence is a major virtue of commitment, which is a combination of the skill of communication with the commonality, or trait of intelligence. Communication can be looked at in various ways. Simply put, it is an expression of ideas that also likely carry emotional energy as well. This makes them similar to beliefs, which have the same structure, but the difference is that beliefs are contained within us, sometimes unconsciously, until expressed to others in communication.
What makes influence unique as a character virtue, is that it affects others in a positive way, through communication that is achieved intelligently. This means that it is strategic, efficient and effective, but not necessarily mature, which would be another matter. Some very influential messages in the public (such as propaganda) are very immature and narcissistic, but nevertheless, effective at swaying the beliefs of others.
If stupid ideas were expressed, they would either not be influential right out of the gate, or they would have relied on emotionality of expression to seduce others into liking and believing the ideas expressed. Influence as a virtue, however, needs to last, and so emotionality alone as a persuader or convincer (such as what many marketers do) is not going to last, and is not valuable to society. Influence IS valuable to society, and as a character virtue in our lexicon, improves society and people's lives.
From Aristotle's Golden Mean, we learn that every virtue such as this also has two vices. In the case of Influence, we may need two descriptors of each of the two vices in order to give color to them. The words for the vice of excess of influence are Manipulation and Intrusiveness, which describe an over-reaching (invasiveness) into the secret or obvious control over another person's ideas ("manipulation.")
You might then see how it is important for us to address the deficit of influence in both of these two ways - the lack of intellectual impact (irrelevance) and the lack of emotional impact (impotence.) This is because communication is composed of both ideas and emotions, bound together.
Many couples have fallen apart in partnership and intellectual attraction, simply because one or the other partner did not have influence - not only on their partner, but on people in their workplace or community. This will make sense as a cause of failure for the couple for this reason: Like anything in psychology, there is a spectrum, and so all people have some greater or lesser degree of influence over others. There is likely no such thing as a person with zero influence, at least over one's mother, or one's children, even if one is friendless.
And so, influence of some degree, no matter how small, is absolutely necessary in every human arena of goals and success - the workplace, in romance, in parenting, in finance, in community service and politics. Even when you go to the store to buy groceries, your competency at being influential will affect whether you are treated with good customer service or poor service.
We might then often see a couple have a falling out, because there was a lack of respect between the partners. The disrespecting partner likely saw how others in the community treated their partner, and soon joined the bandwagon. They may describe their partner as "in decline," or how their "star fell." It becomes obvious to the partner who leaves, that the amount of work that would need to be done to rehabilitate (or ignite the reputation of a partner with low influence in the first place) is far more effort than one has to work, alone.
In terms of having access to the benefits of being in certain social groups that assist one in reaching particular goals, the uninfluential partner offers nothing toward success and is therefore intellectually unattractive.
Influence has bearing on our performance in phase three - intellectual attraction - step eight, where we seek to amplify the best virtues toward our goals.