This is particularly useful information when you build MPE and start the process of contact/share maps/trade techs. Check out all of them before begining contact to better plan the order of contact.
For example, if you know that one AI is researching a tech that another already has, then you visit the second one first so you can trade for the tech and then gift that tech to the first AI and get them researching something else--hopefully something you will need.
Maybe that point is so obvious that "some people" think it doesn't need to be said
...but it took me a while figure it out.
But then I'm not the sharpest knife in the drawer.