Yeah, that's part of what I'm talking about, for sure. Being able to, say, click a little expand icon to see other pins that aren't usually necessary, is great for discoverability. I'm not a big fan of library maintainers deciding that I can only use certain inputs for an underlying function that I know has more functionality. Node authors should, of course, be able to guide, but I don't appreciate them having the ability to control.
More than that, though, it's about the difference between 'data references' and 'execution flow'. It's something that Unreal makes very, VERY obvious. Color coding data types, emphasizing execution flow lines, etc. I can't recommend using it as a guide, enough. Whatever problem I've come up with as 'complicated' for visual scripting, they've got an elegant solution for.
Even stuff like being able to 'break' nodes into other nodes, or pins into other pins. So a "Point" node might be useful for sending into a function expecting a Point data type, but you might also want to send just that Point's x or y value to something else. In that scenario, you might 'break' the exit pins into a Point reference, an x reference, and a y reference. It would be cumbersome and unruly to always have that available. But the UX to make it available is straightforward and satisfying.
And then, all of that aside, I just prefer the visual look of pins integrated into the nodes. The extra lines you get from drawing between the pin and the node is messy and since you can't move them independently, they don't really add anything. Just a lot of extra buffer to prevent a 'crowded' feeling. But at least that's not something unique to Unreal. I don't think I've ever seen a visual scripting system that used pins as separate elements. So maybe it's just saturation bias. But I do like what I like!
Anyway, I'll definitely mess around with it and see if it can help with its embedded version. To be completely honest, I think there's too much friction, overall. I would need something to render as plain javascript, rather than a JSON structure or minified JS (or typescript), so there's a translation there. And then to get it graphically how I want it would be complicated due to all the domain-knowledge required for integrating with your app's underlying library (looks like next js? Not sure, but it's not something I want to work with). Not to be too pessimistic or anything. Most libraries work toward providing a complete solution, not towards providing a composable, compsitable, modular set of utilities, which is what I need. I don't hold any contempt for providing what you've provided because it's a hell of a thing and perfect for a lot of use cases, I'm sure! I'm just very pragmatic about my own use-cases, and my development quirks (like not using libraries that obfuscate functionality [next, react, svelte, etc]).