MathML has terrible browser support [1] and often results in inconsistently rendered, ugly equations.

MathJax and KaTeX are nice but sometimes I prefer not to have JavaScript for these things that ought to be static.

[1] https://caniuse.com/mathml

It's being worked on again though https://www.chromestatus.com/feature/5240822173794304 by https://mathml.igalia.com/