If you already have the maths rendering script in place for more complicated uses, and you don't already know a quick way to insert the ½ character, then it's just the path of least resistance.
I was wondering what you're talking about but then realized that the US keyboard layout does not have the ½ symbol right there in the keyboard like we have in Europe.
I know. I'm from Finland. Look, I'm not arguing that everyone has the ½ in their keyboards. On the contrary, most people don't. It's just funny that some people might think ½ being hard to type and some people think it's easy and it's really dependent on their keyboard layouts. :)