14 is better than 13 and the reason is the constraint, not the use case.
I have run trips with a satellite messenger for four years. What I learned is that a hard character budget quietly forces every good product decision you would otherwise argue about for months. You cannot ship a chat interface. You cannot add a settings screen with nine notification options. You get a fixed vocabulary and you have to decide, up front, what the five things worth saying actually are.
Whereas 13: the degrading itinerary - has no such discipline and will grow into a trip planner, because everything without a constraint grows into a trip planner.
The bit you have flagged as the catch is the real one though. A few days a year is not a subscription. Sell it to the person at home who is waiting, not to the one out there. They are the one refreshing a screen and they will pay monthly to stop feeling like that.