Is Erlang good for regular web application building? If so, what's the recommended way of doing so?
Here's a neat demo. No JavaScript required.
Elixir and Erlang interoperate well so if you want to stick with Erlang you can do the Web bits in Elixir and then do all the lower pieces in Erlang. What happened to me though is that I discovered that Elixir is great, and so is it's tooling.
Building a web service backend serving JSON over REST, or similar? Works well.
Wanting a more "batteries included" Rails like experience, with server side rendering and such? Elixir has a solid framework in Phoenix, and community around it.
It boils down to the complexity that it saves you from. Webapps eventually grow to need caches and queues. That means external infrastructure dependencies on things like RabbitMQ, Kafka, Redis, Elasticsearch, etc. That also means managing the lifecycle of this infrastructure in your application and building robust systems to do maintenance, etc and not fail.
Erlang provides enough of the basic building blocks to trivially implement these features on BEAM in code, as I'm sure you already know. Then all you're doing is message passing with Erlang.
That's the secret sauce. The language features itself don't make it any better at solving the webapp problem than say Rails, etc...it's all of the ancillary problems of scaling webapps that are solved by everything just being code running on BEAM.
[0] https://elixirschool.com/en/lessons/advanced/gen-stage/#