Allied with Katarin as Boris. What is the value of settlements?

Katarin just built a settlement in the howling wastes. It is not near any enemy at current.

Since we are both Kislev, what are the benefits of building an outpost. We are already military allies, so I can see everything the Ice Court sees.

I am thankful for the extra garrison.

But I don't think it will give me access to any new units. Maybe she will get war bears faster than me because I am in the Chaos wastes and cash is scarce and harder to build.

Why would the AI build an outpost there?