But if you really need it, it's really great to have that option (e.g. very long running systems which are split in front/back etc), and it can be used in creative ways too (like the Drone example).
Here is a lightning talk I gave about how to use hot-reload for music / MIDI interactions: https://www.youtube.com/watch?v=Z8sGQM6kLvo
"…thanks to hot reloading, which — for once — is useful…"
That seems to sum up the sentiment that hot swapping in Erlang has uses but they're generally not aligned with what Erlang is typically employed for. It seems like it would be great for tight game dev loop feedback and iteration too, for example, but that's not a traditional use of Erlang either.
Actually, I think it is much more common in original Erlang scenarios (including "non-web") where high availability is a useful pre-requisite.
It is in my experience less common in Elixir, which is often more web-oriented (although not exclusively).