i cant see the logic of withdrawing SWUs at a time when they are all having trouble filling the international flights. The downturn in business travel has had the effect of bringing on better deals for various classes of travel with most airlines. They are valuable, particularly to international travellers doing longhaul flights, but if i know the flight might be pretty empty in economy(eg delhi-lhr soon to disappear) i wouldnt bother upgrading so their value is relative, not absolute.