The importance of self development cannot be over emphasized. One who is self developed is combat ready, you can get opportunities and several doors will keep opening.
A lot of unemployed people are unemployed because they're not self developed, being self developed means adding value to one's self
As an individual, for you to make people to respect you and like you, then you must be better tan they are, you must have something that they don't have. This being said self development in this context involves the balanced process of adding more worth and value to one's sef. As an individual it is wrong to just develop yourself in one area and leave the other area out, doing this would simply lead to deficiency. Even God understood the concept of balancing that is why during creation he didn't just create man alone with one leg and eye, rather He created man's counterpart and all of the body parts where balanced.
So if you decides to develop yourself in the area of skills acquisition, also develop yourself on how to properly channel and use this skill to make more money to take care of yourself and your loved ones. Self development in one area alone is more like doing nothing