Somewhat of a random anecdote, but the first time I realized this was when I was in HS. I participated in what you may call a "hackathon". It was really just a competition open to HS kids that involved building an app to a spec.
I was lucky I have a friend with absolutely amazing artistic abilities, who did a lot of work on our UI and logo and I confidently say we had the best work out of everyone we completed with, both in terms of appearance and functionality.
But when it came time to present our work, I noticed something, while I never doubted our technical competences basically everyone before us had public speaking ability on the level of a politician. Nearly everyone else slaughtered us in terms of being able to present their work to the judges.
At the end of the day, our technical and artistic abilities paid off well enough, placing us just barely high enough to move on to another level, but it was clear, even if we were technically solid, we had approached the competition all wrong. We probably could have placed higher with a worse application, but better presentation.