Being a mathematician allows you to play the game of chess better.

Mathematicians perform calculations quickly and accurately. Mathematicians are creative. Mathematicians are good at identifying the important component to a problem. Mathematicians are accustomed to encountering new problems and challenges. Mathematicians are good at comparing alternatives.

Now consider the game of chess. At any level 90%+ of chess games end as a result of an oversight in calculation. This often happens because one misses a surprising or unconventional move that requires creativity. In chess there are many strategic components, pawn structure, piece activity, material imbalance, king safety etc. but often one of these takes center stage. Almost always in a game of chess there will be a situation you have never encountered before. 90+% of grandmaster chess moves would be listed in the top 5 choices of any tournament player but consistently play the third or fourth choice move is a recipe for disaster even in scholastic chess.

I can not think of a profession better suited to playing chess than that of mathematician!