Yes, and that’s absolutely the case I was thinking of 
It’s a nice to have, for sure! The industry I work in (SaaS software), we use Channels, and it’s not a problem for us to just reboot the servers, because the websocket will reconnect to an alive, not-being-deployed server, and I don’t need to worry if whoever wrote the appup remembered to start the new Supervisor or whatever, we just start at the state we want via application.ex and don’t worry about it.
The downside is, we need to deploy our service one (or a small few) at a time, because if we deploy, say, all the servers (~50+ m6g.8xl on a heavy day) at once, we would have downtime, as well as the dread thundering herd as millions of websockets reconnect and resume state.
We used to use hot upgrades, but the mental burden on the engineers of figuring out “can I do this hot or does it need to be a release” became too much of a headache. Still, it was nice to be able to deploy all of our servers at once (currently takes ~30 mins to deploy the fleet)
