Do you remember practicing your writing in grammar school, and they gave you those pads of grey paper with the blue ruled lines on it? You know, where you had a dotted line to help you make your lower-case letters exactly half the height of your upper-case ones? That was cheap paper, made mostly of wood pulp. Neenah Paper Company wants you to hate cheap paper.
In high school, I became familiar with Strathmore Bristol papers, which have a high percentage of cotton rag in them. Cotton fibers are much longer than wood pulp fibers, so the paper is stronger, and can stand up to being erased a few times without wearing away as if you were erasing your mistake with an orbital sander. Bristol paper is wonderful stuff. I assume this Neenah stuff is similar.
This ad is from 1936, which was a bit of a golden era of Art Deco style. That being said, I have to admit that here we have one example of that rarest of all things - ugly deco.