I develop lots of side projects that I always host in Ubuntu. They are web projects that require knowledge of configuring, stopping, and starting services on the box with ease. I am fully comfortable with upstart - but to learn systemD adds a huge amount of overhead to someone like me with little time who just wants to enjoy coding and shipping fun projects. I don't want to be a fulltime sysadmin just so I can launch a demo or game that nobody will ever use!