Strengths can be weaknesses. It's important to know both ends of the spectrum.
Self assessments lead to better understanding of yourself and how you interact with others, how you operate under stress, why that person drives you crazy and how to improve communication and teamwork.
Are you a promoter? Is he a data-centric thinker? Why does he always take a background role instead of the leadership spot I want him to be in? Why can't she just sit still?
Give yourself and your team the gift of learning more and working better together with confidential DiSC reports.