The reference to weaknesses belongs to an antiquated sense of direction in managers, and management. Knowing your weaknesses has been valued as part of the in most cases worthless performance evaluation rituals of corporate idiots.
This worthless type of performance management, or evaluation is a way to keep the worker focusing on their weaknesses, and hinging pay for performance on areas of lack of giftings.
let me give you an example in how the eastern nations have trained their ping pong, or table tennis players. They evaluate the players strengths, and weaknesses to establish, and prioritize the training time. After establishing the players greatest strength they form a regimen to develope that strength to the point of being able to dominate the opponent through this strength alone. The other greater strengths may also be developed as well, but as far as the weaknesses go.
NONE of the developement of skills time is wasted in areas of weakness, as the chances of return on investment are minimal. This approach does evaluate that the weakness is not due to lack of gifting in that area.
Example: We would not want to waste our time trying to teach a 4 foot 2 inch person to slam dunk in basketball practice. Michael Angelo would not focus his time on non-artistic endeavors. Most stereotypical IT guys would not seek a PHD in socail work.
Reality: Investing a large percentage of your time investing in areas which you have no natural ability, or gifting is just plain stupid, therefore focusing on areas of weakness is generally a waste of time, and has no signifigant return on investment.