Why does someone who play War Need to Trade so Many Storage Parts?

[Skyambler]

I like to know from those who play war. Help me understand

A mayor constantly trades storage items for burgers and it never seems to end.  Is there a need for storage items in war? Or is it because you need many cities to store all your delivery items or is it to store weapons? Or is it to trade and re-trade for more burgers in war?

I am just trying to understand the need for so many storage parts. I took a while but I completely my storage needs in some months.