My understanding is that the high refresh rates are useful for reducing discomfort for users of stereoscopic displays. And one of the potential benefits of 8K

My understanding is that the high refresh rates are useful for reducing discomfort for users of stereoscopic displays. And one of the potential benefits of 8K is to remove all need for antialiasing. Think of it like ray tracing. A dramatically simplified rendering pipeline because it more accurately represents reality without tricks. If you got the raw hardware power to support such things.