Tomato skins are tough and they don’t become tender with cooking. Most people find them annoying. But, they have valuable flavor and nutrients, so some ambitious gardeners (not me!) will save the skins, dehydrate them, then grind them into powder to use for flavoring in soups and stews. Too much trouble for me! But I do submerge whole tomatoes in boiling water for 20–30 seconds before freezing or canning, and this makes the skin just slip right off! Easy peasy. :D