Correct me if I am wrong.  If you like manual lens.  The ability of some Mirrorless  EVF or life view to zoom in to specific area of focus interest, is an asset. More so if lens are long, maximum aperture opening is not really that great, and lighting is poor. 

But do bare in mind EVF may cause problems to some people suffering from serious vertigo issue under certain conditions..

Best you try it out using a very long lens and pan the camera..  you will get the effect almost immediately.  I somehow cope with it .. doing it slowly.