I've been following this proposal around for the past few months, it's really interesting. Godot could be the de-facto library for complex 3D rendering in any app since it's really feature-rich and not that huge (I think the runtime is like ~60 megabytes? It could likely be smaller with further optimization and stripping features you don't need).

Also I don't remember who said this but if this goes through it could allow C# web builds by loading Godot is a library.

Kind of a shame this came as 4.3 is in feature freeze, it would've been nice for it to be included in the next update.