URL structure matter a lot for SEO and search engines ranking of a website. Pretty URLs are those URLs that contains to the point information like product and categories names while Ugly URLs contain extra dashes, words, symbols and signs. Now the choice is yours, do you want to have pretty or ugly URLs in your URLs structure. If your preference is pretty URLs, then you can use a simple tool naming PrestaShop Pretty URLs module to make your URLs clean from useless information. This tool removes all the unnecessary material from URLs and auto redirect the old URLs to new URLs.
To get more information, go here; SEO URLs PrestShop
Watch video guide: https://youtu.be/j8lq4jRq8qQ