Google representative John Mueller, when asked about optimizing e-commerce category pages, noted that if there is too much text on the page, then the algorithm may be confused whether it is an informational page or not.
He suggests some text on the page may help.
The caution is to not go overboard with blindly writing long passages of text. This practice is not actually helpful to customers trying to shop for products.
Lengthy chunks of text exist purely for the sake of the search engines, in many cases.
From my own experiences with e-commerce clients, getting customers to their goal (buying products), having a great design and user experience, and a robust link profile is your best bet for ranking e-commerce sites.
A little bit of text on category pages seems to help in some circumstances — I’ve seen it work.
The suggestion seems to be, don’t write a novel underneath the e-commerce product listings, or the algorithm might not know if the primary function of the page is informational (blog post) or transactional (e-commerce).