The default policy should be that when I save a file it's saved. If they had created this idea that only fsync puts the file on the disk, say, forty years ago, code would be littered with fsyncs (and no doubt filesystem writers would be cheating on that invariant and complaining that people overused fsync.)
Right now, after I've spent 15 minutes working on something and saving my work along the way, if I lose my data because something didn't run fsync in that 15 minutes, I'm going to be royally pissed. It takes a lot of speed increase on a benchmark to make up for 15 minutes of lost work. The time that users lose when stuff goes wrong doesn't show up on benchmarks, though.