From HTML WG Wiki
MathML is NOT a Graphical Markup Language
This change proposal makes several references to content that the author believes should be contained in a
FIGURE element, if such an element is to be retained, listing MathML as appropriate content for a
FIGURE element. MathML is not a graphical markup language, such as SVG, but a semantically-based XML-dialect which can be represented in a specific stylized means -- that is, as a mathematical expression -- but a mathematical expression is not a graphic, but a convention for expressing mathematical functions. Note that the ARIA
math" descends from text, not a graphical representation of the mathematical expression.