After some rigorous internal debate, I think I disagree with this. It makes sense in the context of a web page, but in the context of a web app, the concept of a “link” is nearly meaningless. If most webapps were to implement this standard, they’d simply mostly not use the pointer.
It is far far more valuable in my opinion to have the cursor as a tool in the belt of differentiating between “clickable” and “non-clickable”. Yes, you can also differentiate between this with hover states, but I cannot imagine that “sometimes things you can click have a pointer and sometimes they don’t” ends up being a more usable piece of structure than “pointer means clickable”.
Google does as you say, and frankly, I only noticed that when I went and looked. This implies pretty strongly to me that the usability impact is minimal and that this is an aesthetic consideration.