Scattered storage feels convenient at first but gets messy fast
On day one, it feels easy to put things wherever there is space. By day two or three, that system usually breaks down. Tissues move from a door pocket to the back row, cables disappear into seat gaps, and medicine ends up mixed with snacks. The main problem is not volume. It is that the storage location keeps changing.
One soft bag turns repeated searching into repeated grabbing
The most disruptive items in a private vehicle are often the smallest ones: wipes, tissues, sunscreen, gum, motion-sickness tablets and charging cables. None of them is large, but all of them create friction when scattered. A shared soft bag gives the whole group one known access point for the high-frequency items.
Only a small set of strongly personal items should stay separate
Not everything belongs in a communal bag. Water bottles, phones, glasses, immediately needed medicine, and a child's comfort toy usually work better at the traveller's own seat. A useful rule is simple: shared high-frequency items go in the main bag, truly personal immediate-use items stay with the individual.
The bag should be easy to lift out during repeated stops
Xinjiang road trips involve many small transitions: photo stops, restaurant breaks, seat reshuffles and clothing changes. If your in-vehicle organisation cannot move in one quick lift, it is not really stable. A light soft bag with a clear opening usually works better than overfilling every small fixed storage compartment in the car.