IMO Hot Code Updates are a tantalizing tool that can be useful at times but are extremely easy to foot-gun and have little support. I suspect that the reason why no one has built a nice, formal framework for organizing and fanning out hot code changes to erlang nodes is that it's very hard to do well, involves making some educated guesses about the halting problem, and generally doesn't help you much unless you're already in a real bind.
Most of the benefits of hot code updates (with better understanding of the boundaries of changes) can be found through judicious rolling restarts that things like k8s make easier these days. Any time you have the capacity to hot patch code on a node, you probably have the capacity to hot patch the node's setup as well.
That said I think that someone could use the code reloading abilities of erlang to make a genuinely unparalleled production problem diagnostic toolkit - where you can take apart a problem as it is happening in real time. The same kinds of people who are excited about time traveling debugging should be excited about this imo.