Squinting at things is an easy way to reduce the contrast when looking at and evaluating art to see how it might read from a distance or at a glance or in one of the hundred difficult locations a logo will find itself.
And the reason it is useful to maintain a distinctive shape on a logotype or mark is that shape is one of the vectors that stimulate memory. By not having a distinctive shape, the designer limits the opportunity for recognition and memory. It is just the way the eye and mind relate.
