Awesome write-up, Francesco! To add to the success stories, our team's previous startup (Bugsense) was a huge user of Erlang, which allowed to scale to hundreds of thousands of concurrent devices with just a handful of servers [1]. It was a no brainer that we would now use Elixir for our current startup (AgentRisk [2,3]) and we wouldn't have been happier with our choice, especially paired with Phoenix, which is hands-down the best web framework we've ever worked with.
[1] http://www.erlang-factory.com/static/upload/media/1394234889...
[2] https://agentrisk.com
[3] https://blog.agentrisk.com