Reducing memory consumption in a custom Mesh Component - should I really keep mesh data in RAM after uploading to GPU?

I need to optimize rendering of very detailed generated meshes (using marching cubes).
(The meshes will use only a single material => hence only one mesh section is needed.)

I wrote a custom mesh component which uses built-in FStaticMeshVertexBuffers.

But I noticed that vertex buffers in FStaticMeshVertexBuffers, for some reason, keep raw vertex data in system memory.

Is it possible to avoid that waste of resources by coding custom vertex buffers that don’t store copies?
(I’m afraid that this duplication is dictated by the engine’s design.)