Even though there's non-magnetic material that can be carried catching any magnetic particles that are there cannot be bad. The tranny pan on one of our past Jeeps had a magnet sitting in the inside of the pan, held there only by magnetic attraction, and after 30K miles it had a thin coating of extremely fine material, almost like a slime it was so small. Like Bug, the magnetic oil pan drain plugs seem to always have a small amount of "stuff" attached. Can't hurt.