ive tried googling it and nothing useful comes up. the unreal page just has functions for it, doest actually give a description. what is the difference between a static mesh component and an instanced static mesh component and why would you use one over the other?
A staticMeshComponent can hold just a single copy of a staticMesh.
An instancedStaticMeshComponent can hold multiple copies of THE SAME MESH. it is used to have a lot of instances of the same mesh in the screen because this component uses the same memory allocation of the mesh (and materials) for all the instances and the heavy lifting is done by the GPU. the only difference the instances can have is the transforms of each (scale,rot,pos) and custom data floats variables. All instances have same LOD so if you also need LOD for your mesh there is hierarchical static mesh component too.