I was thinking of developing something similar, but it ended up being one of the thousands of ideas that never end with a line of code. I'm glad to see it here.
Visual programming is a tempting idea I love. It rarely works, but this might be the case.
I think there is a lot of room for AI UIs - between chats (the simplest and most prevalent) and arbitrary code (even if it is "just API calls", it is only people with at least some software inclination).
One thing I am keeping track of is WordWare (https://www.wordware.ai/), which makes it easy to create a sequence of operations. It feels like an "Excel formulas of AI".
Yet, I like the visual, graph-based approach of Tldraw.