I drove my last Mog for a week or so without a windscreen mounted mirror when I fitted the folding windscreen and I was amazed at how nicer the forward view was without it being there
I did fit a small dash mounted mirror later and I didn’t really consider the idea of going without a rear view mirror but if you don’t need it for an MOT and the door mirrors do the job for you, I can see the positives for the freeing up of the forward vision