A wildcard stands for another symbol or numerous characters in search command, e.g. asteriks (*). In case an admin needs to find all the Irish zip codes with the Shipping Table Rates extension, he/she can use the wildcard '%' instead of some variables, e.g.: E12%4.
You can apply the priority option to shipping methods only in case you need to choose the rate for the products that meet the requirements of two or more different methods. Shipping methods on the checkout page are being sorted by native Magento functionality and don’t depend on the module settings.