[nadam]

An example is the material editor. When dragging a value of a property of a node (like color) you see it immediately in the editor. You apply a material on an object, (regular object, water, Landscape), and while changing stuff in the node graph, you can see it applied to the object on the scene almost immediately (depending on some factors of course). A Material can be as complex as a Landscape auto-material which magically auto-generates the surface appearance of a complex landscape (with even foliage). But this is just an example, there are other node graphs in Unreal, like PCG. Hot-reloading my C++ code is not strictly necessary as I write C++ code mostly for really messy complex stuff, where I need to think a lot between tests. So I think Unreal mostly has immediate feedback where it is most necessary.