It's expectation. Think of all the screens in your life that you interact with and when you can't touch them it feels broken (at least to me). So I don't use my laptop as a tablet but when some dialog pops up I want to touch the cancel button. Or I'm helping someone with a task and reaching to move a window directly is natural.

So it is just table stakes at this point.

> when some dialog pops up I want to touch the cancel button

I have never had this. I don't think this is the expectation among people using laptops either? Pressing escape is much faster, doesn't obscure the screen, and doesn't require me to aim.