The fortress docking arrangement Tipid wants, letting Princess Posse airships tie up directly from the stronghold.
Tipid gives a concrete reason for merging the hilltop stone building with the Bait Shop shack: building the whole Stronghold around the wood shack will allow the faction's airships to dock directly from the fortress. That capability, plus the changed Saferoom rules, is why the two structures are being wrapped in girders and joined.
The need is immediate — Louis, Katia, and Bautista are inbound with Party Planner — and strategic, since striking the Naga on a distant border will require moving troops by air.
Planned fortress feature letting airships dock straight from the Princess Posse stronghold.