It has an excellent UI, selections work way better than Lucid or Figma etc, the sketchy look makes it clear designs are rough and not blueprints, it's private and loads instantly.
The one negative is that it's a pain to get the multiplayer self-hosted version running.
Excalidraw is excellent for low-friction sketches.
A self-hosted version with storage (multiplayer) plus any Claude access would be a killer setup for team planning etc and let us drop Miro.
TLDraw: https://www.tldraw.com/
Excalidraw: https://excalidraw.com/
TikzMaker: https://tikzmaker.com/
The three-lines-menu also has a "Save to..." option that lets you create a sharable link or save to your local disk.