In my experience cross-platform means "runs just as badly everywhere". They pretty much never feel like native on any platform.
And what's the advantage to the average user? If I'm a Mac user, I'm interested in Application X working just like every other Mac application. Similarly if I'm a Windows user. I'm rarely bothered that Application X works the same on both Windows and Mac.
And what's the advantage to the average user? If I'm a Mac user, I'm interested in Application X working just like every other Mac application. Similarly if I'm a Windows user. I'm rarely bothered that Application X works the same on both Windows and Mac.