Anthony Ramos plays a fictional character in "Dumb Money."Sony PicturesGameStop could earn more from interest on its $4 billion cash pile than its core retail business. Recent hype sparked by the return of Roaring Kitty has allowed the company to raise $3 billion.The company could see $200 million of annual interest income by simply holding short-term Treasurys. GameStop has raised a lot of cash recently, and the struggling video game seller cou…