But it definitely increases notifications for people involved in the review. "A war room for each pull request" you'll exhaust your reviewers very quickly with this mindset.
What about cases where any one random reviewer (or several) is needed from a larger group of people? Does everyone get paged in?
Or cases where a single reviewer is assigned to multiple different reviews? This becomes a DDOS attack on the human attention span and has the potential to create disorientation more than anything.