Well my project is still on 4.19, I havent updated to 4.21 yet so I dont have area lights and I am new to unreal but Ive found it difficult to get away from the very noticeable circular area of effect from spot and point lights in tight spaces. And in order to bounce enough light to get an architectural feel you end up with a bright spot. I know emissive wont cast shadows on moveable objects but Im less concerned about that. The nice thing about emissive is it matches the shape of the object emitting light and gives a nice architectural feel. Plus it just happens automatically rather then having to place actual lights next to every light source. But perhaps Im not doing things right, Im used to lighting in non-realtime renderers 
So my example - the tan image below is a spot light, has a very noticeable circular area on the floor(and bright) but bounces to the other walls well. The blue area is all lit by one emissive plane and has a less distinct, softer hotspot and still bounces very well.