What is the use of a person if he gains the whole world, but damages his soul?

First of all, you always need to think about yourself and your own comfort. You do not need to strive to conquer the whole world, you need to create conditions that will be favorable for your own life. Then happiness can be found.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.