Someone on quora asked:
Selling is really just a form of communication, and it doesn’t apply only to selling products and services to other people for money. You’re selling whenever you’re applying for a job, or suggesting a place to eat, or trying to woo a girl.
Engineers such as myself sometimes look upon selling and salesmanship with disdain - when I build/develop a good product, shouldn’t people just want to buy it because it’s good? Why do I have to spend effort to convince people to buy it?
But the fact is there are far too many things in life competing for your limited resources - money, attention, and time, so you have to be able to decide which ones to pursue and which ones to set aside. And when making these evaluations, the options that sell themselves more or present themselves better will come out on top. So yes, the ability to sell is really quite a useful skill in life.