Recently I did a multi-day hike through some areas in the alps with very very poor network reception so that I was unable to upload my activities in the form that I wanted them to be (nice description & couple of images).
After ending my activity after each hike at the end of each day, Strava tried to upload my activity to publish it to my feed. In areas with poor network coverage this process may not work and causes my phone to retry the upload over and over again which causes an increased consumption of battery (which is not good if you are in remote areas).
Feature request: When ending an activity provide the possibility "Store as draft" which stores the activity locally on the mobile phone without triggering an upload. The activity is then saved and can be edited and published at a later point in time when network reception is better and the activities are ready to be shared.