The thing is Phoenix can be the presentation layer. Phoenix is a full-featured framework, including (in traditional sense) the frontend. Not every website has to be overengineered into a distributed system by building a SPA.
Anyway, I think Time and Date datatypes in Elixir are mostly encountered when working with Ecto and Postgres, not on the frontend side of things. So you can see it’s a more universal data type.
I think it wouldn’t hurt it they were in a separate library but this way we have less fragmentation. And only the basic datatypes are included, libraries are still useful for extending calendar and timezones functionality.
When it comes to the Call for proposals, it does not say we should include all functionality in the standard library, but that we should support timezones with these datatypes in a standardized fashion. Libraries will still be often useful for using these datatypes. See:
