[brainfish]

I think this is a false equivalence. The content of SVGs is non-semantic; to get from SVG code to Meaning one needs to do some sort of rendering and re-interpreting of the resulting image. Even if for some simple images that could be done in-brain, that is not usually the case. Whereas something like Mermaid is intended to be meaningful both as code and as rendered output, just like Markdown itself. Having that additional meaning inline can be very helpful to faster understanding of the content, which is not usually going to be the case for inline'd SVG.

[dijit]

I don't know if it's a false equivalence, because I've read (and certainly written) a fair number of mermaid diagrams which are extremely hard to understand without seeing the rendered content.