For centuries,¬†punctuation served as a rhetorical device, i.e., to guide the reader on when to stop or pause when reciting a text. Today, punctuation mainly serves logical functions in written prose, scientific literature, and mathematical expressions, modifying the tone and providing structure.
The rules for writing numbers vary by academic discipline. While numbers are not a special focus in standard prose, they are in technical, scientific, or medical texts. Numbers written as numerals emphasize quantity more clearly than numbers spelled out as words. Here's a summary of the rules I generally