Lionel gave MTH license to put their name on some of their tinplate reproduction stuff. The logo "Lionel" makes it much more valuable (at least perceived name brand recognition) compared to the same item that just says MTH. Outside of the train world few people have heard of MTH while Lionel is a household word. Even in the hobby,MTH is an off brand to some. The reproductions are pretty much the same other than an added name tag. Strictly a business decision which benefits both companies.
Dale H