- Mermaid has over 8 million users; GitHub added native support in Feb 2022

- AI diagrams are static images. You can't grep a PNG.

- Git diffs on binary blobs are meaningless six months later

- Regenerating to fix one box might break three others

- The 15 minutes you saved skipping Mermaid syntax? You'll spend them on regeneration roulette

TLDR: Learn Mermaid. And if you need ASCII art, you can use https://github.com/lukilabs/beautiful-mermaid