I never had a pickup truck, but I did have seat belts and booster seats. We just didn’t use them as much. But that’s not really relevant to having enough space in a vehicle. We had plenty of space in cars. There was nothing wrong with the size.
It absolutely is relevant. If you don't have to wear seatbelts you can fit four or five kids in the back seat of a sedan. If each kid needs a seatbelt then you have to buy a bigger vehicle.
