The exact point. It would be a good way to see what new posts/threads are, but not if it's filled up with the same ones all the time, especially ones that aren't your cup of tea.
A lot of people probably don't use it for that very reason.
Maybe this could be a PFM perk!
I do see what you mean as when some topic is hot, for example, a thread about hatcheries, it will keep popping up every 10 seconds. I highly doubt ignoring the dozen people who are posting on that thread is quite worth all that effort, and, I wouldn't want to...