Regarding the food tube

I have read about PVC tubes being used for a buried cache. Some may put in it a survival kit or food ..etc.. In such case I understand the use of tough material like PVC to hold the survival gear underground. However, when you need to carry it with a shoulder strap, the straight hard tube isnt comfortable to carry for a length of distance. A soft duffel bag is much better for that purpose and it can douple as a sleeping pillow.

Am I missing something here ?