That makes sense. I'd guess the main reason people use Bitbucket over Github is "free private repos," with "we already use other Atlassian products" a close second.
The only reason I looked outside of GitHub was Bitbucket's free private repos.
Now, for our academic lab, we're working entirely with Bitbucket (for the UI), and repositoryhosting (for low-cost repo archival with many users).
In an academic setting, where private repos are created for each small collaborative project, then left idle but accessible, GitHub's per-private-repo pricing model is prohibitive.
