Blueprint foliage performance

Since it’s now possible to paint blueprint actors as foliage I am wondering how this would impact performance. I made a few tests and figured that draw calls for blueprint foliage are way less than with simple static mesh foliage. Is this because blueprints are instanced by default and therefore only drawn once and then “copied” for each instances transform?

The other thing I noticed was that even if draw calls would go down, other calculations, especially “RenderViewFamily”, “DeferredShadingSceneRenderer” and “InitViews” increase drastically. Could someone please explain what exactly is the reason for this?

Finally I would like to know if I should rather use static mesh foliage if possible or if I’m good to use blueprint foliage for all or at least most of my foliage, for example if I wanted to populate a dense forest.