The semantics of the BEAM VM and Erlang Run-Time System (ERTS) are much closer to the typical semantics of a large dynamic web app backend than those of Python. No surprise there, it was designed to support telephone exchanges. It provides facilities natively that have to be "bolted on" to Python.
I might still write a prototype or proof-of-concept web app in Python, but for anything more serious it seems to me that the advantages of Erlang loom large (and that's before you get to Phoenix LiveView: https://www.phoenixframework.org/ )