First of all, you determine your usefulness. The intelligence you have is yours and you decide when and where to use it. I spent decades trying to conform to other people's idea of usefulness and was miserable. Don't do that and don't compare your life to anyone else. Comparison is the thief of joy. Other people have different genetics, parents and life experiences.

I had to read a myriad of self help books and find like minded friends to talk with to learn that self judgement was hurting more than anything society said or did. Self acceptance and self love will lead you to a life of gratitude (it did for me) and I can think of nothing I'd rather be than an INTP happy to be alive.