UVs input is 2 gradients (horizontal and vertical) in X and Y channels
Texture takes it to map pixels from left to right and from top to bottom
So, in your case, small UV values becomes red, medium is green and values ~ 1 is blue.
In this case you just plug one channel into UVs, so X and Y are identical.
And it simply distorts you texture.
to better understand this effect try to multiply UVs on some small value and grow it.