Yes, even without *A benefits (*S or *G), having a MLL card will entitle you to enter not only a United Red Carpet Club, but also Lufthansa Business Lounges.

http://www.aircanada.ca/services/bus...esentation.pdf

At CDN$375, this is a pretty good deal. Beware, however, that entering a UA or LH lounge is not the simple process of waiving your RCC card. Often they'll need to see your boarding pass and they'll log your name and ID so that they can obtain revenue back to AC.