Let's say you're working on some feature and for whatever reason you need some help. Maybe it's a bug, maybe you can't get the code to build, whatever. Your colleague, who is on the other coast, offers to help. "Let me see exactly what you've got," she says. Neither of you think it's a good idea to push your broken code to the upstream server just so she can see what you've got, so instead she pulls straight from your repo.
Or, maybe you've been called away for a family emergency/hit by a bus/fired for excessive competence/transferred to another project effective now, and all you had time to do was to commit to your local repo. The poor intern who has been tasked with finishing what you were doing needs your half-finished code, and the expedient way to get it is to pull from your repo.
There are all sorts of scenarios where someone might need to pull from a working repo. It's not something that's part of most people's standard operating procedure, but it's pretty cool that git
is flexible enough to make it easy when you need it.