1. Readability is probably the biggest reason. I don't have to worry that some base object changing what I am thinking is happening. There is little magic and it is easy to follow.
2. Let it fail, elixir and erlang you have to write code assuming it is going to fail and handling when it does. Most other language you have to write that code all over in your logic code. Elixir and erlang you do not (readability again).
3. OTP! There is a great distributed framework that erlang and a bunch of much smarter then me programmers built over the last 20 year that I just get to use. Also you can send functions and code over the wire as well to run. Making some very interesting things that are just impossible to do in other languages.
These are just a few reasons. I do build mostly build web applications for business apps. So because of that this is a really good fit. I don't think it is the answer to all but it has been expanding fast.
The one thing I wish it had would be that your dependencies were yours only. I think this is one of the big reasons Node.js got successful so fast. In node you can run different versions with-in the same app depending on the libraries. Elixir is more like ruby in that you can only have one. Well you can have two for swapping out without down time but that is it. I do think this is one of the limits to the Erlang VM.
> Also you can send functions and code over the wire as well to run. Making some very interesting things that are just impossible to do in other languages.
Well, you could do this in any language that has 'eval' really, which includes most dynamic languages. Unless you're referring to something else?
Erlang provides location transparency for processes, meaning that you can send a message to a Pid (process identifier) as if it were running locally, when in fact it's running on another VM on another machine.
I can't speak for Go, but Elixir has a much more sane concurrency model when writing web services (or otherwise) than node. The ability to block a process means you don't need to dork around with callbacks or promises or anything, your code looks like it executes in serial. No shared memory either, so one request can't break another.
The set of abstractions OTP provides map onto web services perfectly. Once you write stuff in erlang/elixir going back to another paradigm is really quite hard.
