No, near-sightedness and mirrors don't work that way.

If it did, we could use mirrors instead of lenses. Want proof? You need your glasses to see yourself in the bathroom mirror, right?

There are fans here of helmet/glasses mount mirrors, and those of us who prefer bar mounts. It's really a personal preference matter.

All bar-mount mirrors are subject to some vibration. This does not make them useless in traffic.

Just because I can't read the license plate of the car approaching from behind doesn't mean I can't see the car. Maybe I can't tell if it's a Hyundai or a Toyota (Who can anyway without reading the nameplate?) but I can see that I don't want to move over for a left turn in front of it.

Now, I wouldn't want to shave in a bar-mount mirror, but I don't shave in traffic anyway. Close shaves BY traffic excluded, of course.