I don't really agree with you being downvoted; I love LaTeX, I use it for basically any kind of mathey stuff that I need, but it is an objectively irritating language, especially for beginners.

That said, the fact is that for mathematical equation editing, for better or worse, TeX-based systems have a near-monopoly on high-quality typesetting; KaTeX giving us a fast, easy-to-use implementation of it is still a net good.