norodnik, flying for more than 15 hours isn't for everyone but that doesn't mean it isn't for anyone.
Believe me, people don't fly all the way to Australia/NZ etc just to have a 3/4 hour stopover in Singapore or KL. Aircraft limitations have necessitated stopovers, but I guarantee you that if it were more economically viable to fly direct from say LHR-SYD, we'd all be doing it. Why, because it'd be cheaper.
From a business pax point of view, if I had to be in SYD on a Monday morning, and had a choice of leaving on a Fri night or a Sat morning, I'd probably take the Sat morning flight to have an extra night at home with my family.
It's horses for courses really.....