An odd thing is that Phil Mickelson, the 'leftie' golf champion, is naturally right-handed. It might be a help on ordinary courses, and to ordinary players, because the courses are designed to hinder right-handers who slice or fade the ball, but most pros naturally hook it or draw it, so he'd be as hampered as a right-hander.
But it's an advantage to be leftie in most sports. The right-hander doesn't meet many , whereas they meet plenty of right-handers. There are two sports that don't permit left-handed play. One is polo. The other may be hockey.