Star Trek creator didn’t want a bald captain.
Star Trek creator Gene Roddenberry didn’t like the image of Patrick Stewart as the captain. He thought he was a talented British actor but simply didn’t think he was a good fit for the role, amongst others, because he’s bald. In fact, he wanted the actor to wear a wig when he auditioned. The president of Paramount saw that audition, and when it was over, he said, “Hire the English actor, but take off the wig.”
Of course, this hand gesture means "read between the lines"...
He came up with it for the character. He's the reason it's in the show. That's all that anyone needs to know. Pointy ears weren't a new thing, either.