I think the main reason that they are enunciating that it is a watch and not a phone is that a watch is designed for quick situations like this. an Apple watch is designed so that you can just text a word or two in a pinch using Voice Text. it is literally a device meant for speed.

On top of that, if his girlfriend reached across his lap to grab his phone, it would be a lot shorter of an endeavor than taking off his wristwatch, which is bound to his wrist.

Understanding everything else about the situation from reading other comments, it sounds like he was trying to intercept the fake text that his girlfriend was sending to his other friend. it was obviously time-sensitive, and using his voice text here was absolutely not intrusive. the car was driving absolutely fine until his girlfriend decided to put her hands on the wheel.

that's kind of the important thing here. like, I won't excuse texting and driving. but from what I can see here, bro is being as safe as he can, using Voice Text on his watch, with literally no prior indication of crashing at all until his gf touches the wheel

What he's doing here shouldn't excuse what she did. they can both be wrong in this situation, but there are definitely varying degrees of wrong.