Time is passing very quickly for Holo, and the settlement is causing her depression, so they must travel to stabilize her perception of time alongside Lawrence. That's why they decided to do it.
Art isn't bad, it's just different from what we're used to. If this were the art used in its first adaptation, everything would be fine, and you know it—only nostalgia makes you say that.
I'm not ready for the ending. Holo must be prepared to face loneliness again, even though she now has a daughter. Still, accepting that Lawrence will no longer be there is going to hurt her a lot.