Why is it not helpful to view the specimen in the microscope using one eye?

Question

Why is it not helpful to view the specimen in the microscope using one eye?

Answer 1

To use one eye to view specimen in a monocular microscope for longer time can cause  eyestrain and muscular fatigue, which does not happen using a binocular because you don`t need to keep one eye closed.

But it makes it possible to draw the specimen with one eye while observing it with the other.

Today most people use a digital eyepiece for documentation, but some years ago it was the best way to draw as correct as possible