Firstly, packing vertically take-up less space which means you can use the full height of your suitcase.
This way you have even more room for other items you might need for your trip.
Secondly, weight is not applied to the clothes at the bottom and therefore limits wrinkles.
Thirdly, vertical packing means you can more easily see everything in your suitcase at a glance.
If you’re worried about staining from other items in your suitcase there are a number of ways to avoid this problem.