Hi,
Note that the description uses HTML and the editor you have to edit the description of a product is a HTML editor.
In HTML, CR and LF characters are not "displayed". To have a line return in HTML you need to have a HTML tag
So in that case, what you could do is change the "Description default format" setting to "markdown" instead of "HTML" in the HikaShop configuration.
In that case, for new products, the description will be added as markdown and the CR / LF characters will be taken into account. But you won't have a HTML editor when you edit these products anymore as you'll have instead just a text area with the use of the "markdown" format:
en.wikipedia.org/wiki/Markdown