No you don't need to concern too much about these warnings. Since some weeks google got aggressive in making this warnings. Rich snippets are no direct ranking factor, but they can help indirect.
An example: If you have rich snipped correctly implemented for ratings. You have the chance that google shows stars for your products. This can help, that more people click on it. BUT what if you have 0 reviews for a product? Then google will warn you and you can't even do something, since you just don't have ratings.
In short: fix the one, who takes a few minutes. But invest the hours in improving your shop in general. (Descriptions, Images, Blog posts, Newsletters and so on...)