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

You're not going to operate Class A on solar panels and it is the opposite of going green. What it can be when properly designed is a fabulous sound that's very involving, Hey folks all Class A aren't created equal, just like Class D or Class AB for that matter.

No, this is not going green at all. I would personally compensate with other things, and others could too.
So, with less than capable speakers and headphones class AB can sound better ? Even if we are talking about excellent class A amp ?

So, with less than capable speakers and headphones class AB can sound better ? Even if we are talking about excellent class A amp ?

Who’s saying this rubbish, you get rid of transistor Class-B xover distortion when you bias higher into Class-A so long as everything else is unstressed.
Unless xover distortion is liked🤦‍♂️🤦‍♂️🤦‍♂️🤦‍♂️

Cheers George

So, with less than capable speakers and headphones class AB can sound better ?

It can sound better even with great speakers! The sound of any amplifier is always about what distortion it makes, and what distortion it doesn't. You can prevent crossover distortion in any AB circuit, since its a function of push-pull rather than whether its class A or not. The only exception is if the amp is operating class B but I don't know of a single example of a class B amp in high end audio.

The sound of any amplifier is always about what distortion it makes

The sound of ANY amplifier is better without ANY distortions whatsoever. (Sure some distortions are not AS bad as others.)
So long as very little distortion is NOT attained by using means that create other problems areas EG: like masses of feedback global or local, global especially!
And there no such thing as "good" sounding class-B xover distortion!