I have several different types of legwarmers. Where I live wRm cloths are necessary. What I like about the leg warmers is they keep you warm with less bulk and you cannot see them under your pants unless you want to wear them over your pants which is an option also.
If your legs are cold, wear long johns. If you find the ones you have are uncomfortable, take them off or shop for a different type. Different fabrics, materials and fit all influence how warm you will be when wearing them.