Thanks for registering on the forum, and thanks for your question.
While examples can be found of Small Wall Tents being used as storage facilities, they were mainly used as either an admin tent or in some cases an Aid Station. For example as the atatched image (which was taken on 22nd July, 1944 at Fort Devins) clearly shows the use of a Small Wall Tent in the role of a Battalion Aid Station.
Illustration from US National Archive clearly showing the use of the Small Wall Tent in the role of Battalion Aid Station. Also of interest is the use of litters to hold up the lyster bag at extreme right of picture.
Hope that helps, if you need any more info, please don't hesitate to ask.