Yes that's essentially my thoughts though perhaps a later feature would be to support the tool customizing d2 files as well! I also think another part about starting with supporting mermaid syntax is that the AI coding agents seem to emphasize mermaid in particular [1] so if they are writing in that syntax anyways I feel it will be even more the norm.

[1] https://cursor.com/docs/configuration/tools/mermaid-diagrams