Why would anyone want class AB amp when class A always sounds better ?

All of the above X 2

Respect

Why would anyone want class AB amp when class A always sounds better ?

Because Class A does not always sound better. Obviously.

class A always sounds better 

Who says?  Absolutes are rarely applicable in this hobby IMHO. 

Yes, they are sometimes applicable.
Miller, what's wrong ? Give us an example. I'll give it myself. Gryphon Diablo 300 class AB integrated sounds better than Sugden class A integrated. But it's not a fair comparison, not what I mean, of course.

It's also often that current matters no less than wattage, at least.