Not sure how well they would work in NW slushy snow ice....midwest, where it is colder, drier etc. They frankly, probably work pretty well. As they noted, many of the european cars have low clearance for cable or chain chains. So one needs a lower clearance/thinner volume help in some extreme cold snowy conditions. THese would appear to work well. Reality, if made correctly out of some water proof material, not cotton or wool, they should last a reasonably long time. But driven on literally a hard concrete surface, like metal chains, they will not do well for long.
marty