Many of us here frequently use MathJax, whether for this site or another site on the SE Network. Recently SE added support for tables, but ignored the needs of the communities with MathJax support, who wish to be able to type TeX symbols/formulas/etc. as well.
Here's some network-wide examples where such support would be needed (please add anymore if you're aware of any!):
- https://mattermodeling.stackexchange.com/a/1257/5 (here MathJax is only needed for 3 symbols and the rest doesn't need MathJax at all, so it's the perfect example where Markup tables mixed with some MathJax expressions would be ideal).