HMMS, well yer right on one point, although it is known who goes through, it is still not known who will be 1st after the rest of the matches are played. So I gues they oughta be played. Uhm I dont actually care all that much, I gues another week more or less of competition time doesnt mean much...
Since the semis are 1st vs 2nd, it would prolly be quite important who the is the 1st and who the 2nd.