A twenty-room property does not fail because it lacks features. It fails at the seams: the booking that exists in the inbox but not on the board, the restaurant charge that never reached the room, the morning where nobody can say what last night earned.
The joins that matter are few and specific. A reservation must attach real rooms for real nights. Those rooms must feed a board that housekeeping and reception read the same way. Every charge from every outlet must land on one folio. And the day must close once, into a figure nobody can quietly rewrite afterwards.
Vestibel builds all four on one anchor: the Party, which is simply the people being billed. A stay is a party, a dinner table is a party, a spa booking is a party — and each has exactly one folio. That is what lets an outlet bill be posted onto a room bill as a single line instead of being carried across on a slip of paper.
The test of whether a stack is really joined up is checkout. If the desk can see, on one screen, every open bill anywhere on the property that belongs to the guest in front of them, the joins are real. If it cannot, they are not.