The Just In Case solves a different problem from your main luggage: you may not need a second backpack on departure, but you may want one once you arrive. Its foldable format is the reason to consider it.
Give the spare bag a planned assignment
The linked TUMI version is described as lightweight and foldable, with black fabric and gold hardware. A clear use is a destination bag for a light layer and daily essentials, allowing the main travel pack to remain at your accommodation.
Another is separating a small set of possessions for a day excursion. Decide what those possessions are before packing the spare. A backup bag that has no defined job can become just another object taking up space in your primary luggage.
Extra space is not an extra baggage entitlement
Opening a folded backpack creates another container, not permission to bring another item aboard. If you expect to return with shopping, plan how the bag will fit within your booked baggage allowance or inside the rest of your luggage. Counting bags on the return trip matters as much as counting liters.
A foldable bag also deserves a different packing approach from a heavily structured laptop pack. Put sharp-edged objects in a pouch and choose a light load that remains comfortable against your back. The listing does not establish a padded computer compartment, so do not assume that protection is present. This is an appealing accessory for a traveler who already has suitable main luggage and wants a compact answer to a specific second-bag need.
