Is it a trolley bag or a trolley case?

Q: Is it easy to use a trolley bag or a trolley box? Answer: The case is soft when it's wrapped. Think of someone else's overweight, oversized case wrapping the contents of your bag around you when you check your luggage Still not completely crushed or pull bar box practical. First, the box is more balanced, the bag force is not uniform, so even if more pulley or easy to tilt, unstable second, the box is larger than the bag space. Third, the box is harder than the bag is softer, not easy to damage. Fourth, the box is higher than the bag safety factor!