Unfortunately the documentation for Erlang doesn’t really describe any pros/cons for anything and I’m not an expert in it so I don’t know what the limitations are for the Erlang approach but they certainly must be (e.g. if you have long running sessions and do several upgrades, are you running N versions of the code & eating up RAM because the old sessions aren’t complete?).
As I understand it, Erlang/OTP captures the entire state of the program and it’s a feature of the language and VM to accomplish this. It’s not something you can retrofit into any arbitrary language. For example, your JS app or your Python app or your Rust app won’t be able to do the same easily which means it won’t be robust and it will be error prone. Thus I stand by that there’s no “generic” solution you can bolt onto an arbitrary language.
As I understand it, Erlang/OTP captures the entire state of the program and it’s a feature of the language and VM to accomplish this. It’s not something you can retrofit into any arbitrary language. For example, your JS app or your Python app or your Rust app won’t be able to do the same easily which means it won’t be robust and it will be error prone. Thus I stand by that there’s no “generic” solution you can bolt onto an arbitrary language.