It's more space, and that way the people of Hinoto-Ri won't be paying for our utilities anymore.

C'mon. We can share it! It'll be way better than the tiny apartments we've got now.

[It goes unsaid, but Ayumu would also have an easier time keeping an eye on Hizumi. But Hizumi wouldn't mind it all that much, either; he enjoys being with Ayumu as it is, even if he's being observed all the while.]