Here’s what he said
"
Ok, for each copy of that blueprint you are getting a draw call on the static mesh it is spawning.
The reason instancing saves performance is because draw calls are limited by only have 1 mesh that is then copied without the same overhead.
So if you have an instanced mesh, say a Tree, you want all of those trees coming from the same blueprint. You could put other instances in other blueprints, but that really depends on what you are doing.
"