[joehosteny]

We use it in our robotics startup, and I wholeheartedly agree.

As an example, we just rolled out a feature in our cloud offering that allows a user to remotely call a robot to a specified waypoint inside a facility, and show real time updates of the robot's position on its map of the world as it navigates there. We did this with just MQTT, LiveView, Phoenix PubSub, and a very small amount of JS for map controls. The cloud portion of this feature was basically built in 2-3 weeks by one person (minus some pre-existing code for handle displaying raw map PNGs from S3, existing MQTT ingress handling, etc.).

Of course you _can_ do things like this with other languages. However, the core language features are just so good that, for our use cases, it blows the other choices out of the water.