Honest question: how do we know for sure it's not CG?
CGI modeling of a shattering string instrument that looks realistic would be an insane amount of work, and insanely expensive.
This was definitely mostly practical. The squished emoji ball at the end might have been CGI, but not most of this.
If you look through it you can see the top of the guitar is even cut off at the neck, either as a prop or digitally.
Movie magic, guys!
Also if it was CG Apple would have immediately said that.
You can actually see that they repositioned the ball between the side shot of it rolling and the front shot of it getting squashed, which you wouldn't need to do it if was CG.
You think they got a real ball to roll out to the edge and filmed that live? Ridiculous.
I would be surprised if any of it was real.
The Corridor Crew YouTube channel taught me that CGI is everywhere and I don't have a clue. Highly suggest checking out some of their videos.
But there's also the bigger factor that, if Apple didn't destroy a bunch of stuff, why haven't they said so? It seems to me that if this ad was entirely CGI, Apple would admit that to minimize the backlash.
Therefore, unless Apple says something (or someone does some very convincing analysis), I'm inclined to believe this ad was done primarily with practical effects. That's just where the evidence is pointing right now.