Originally Posted by
wowzz
Personally I cannot think of any advantages, but I stand to be corrected.
At least two more I can immediately think of:-
1. Complex itineraries, eg LHR-(QF)-SIN-(JL)-KUL-(SQ)-SIN-(QF)-LHR, which most online sites won't easily deliver. Ironically, one of the first real online booking sites, easySabre, was also the best in this respect; it was a more powerful website than anything readily available to the public now.
2. Tame consolidators who will reserve your itinerary on a net fare, but will hold off ticketing until the airline's ticketing deadline so you don't have to hand over any cash at all until that point (as well as retaining full flexibility to cancel for zero penalty until ticket issue).